Understanding the Degradation of Methylenediammonium and Its Role in Phase-Stabilizing Formamidinium Lead Triiodide.

Formamidinium lead triiodide (FAPbI3) is the leading candidate for single-junction metal-halide perovskite photovoltaics, despite the metastability of this phase. To enhance its ambient-phase stability and produce world-record photovoltaic efficiencies, methylenediammonium dichloride (MDACl2) has been used as an additive in FAPbI3. MDA2+ has been reported as incorporated into the perovskite lattice alongside Cl-. However, the precise function and role of MDA2+ remain uncertain. Here, we grow FAPbI3 single crystals from a solution containing MDACl2 (FAPbI3-M). We demonstrate that FAPbI3-M crystals are stable against transformation to the photoinactive δ-phase for more than one year under ambient conditions. Critically, we reveal that MDA2+ is not the direct cause of the enhanced material stability. Instead, MDA2+ degrades rapidly to produce ammonium and methaniminium, which subsequently oligomerizes to yield hexamethylenetetramine (HMTA). FAPbI3 crystals grown from a solution containing HMTA (FAPbI3-H) replicate the enhanced α-phase stability of FAPbI3-M. However, we further determine that HMTA is unstable in the perovskite precursor solution, where reaction with FA+ is possible, leading instead to the formation of tetrahydrotriazinium (THTZ-H+). By a combination of liquid- and solid-state NMR techniques, we show that THTZ-H+ is selectively incorporated into the bulk of both FAPbI3-M and FAPbI3-H at ∼0.5 mol % and infer that this addition is responsible for the improved α-phase stability.

The International Academy of Cytology Yokohama System for Reporting Breast Cytopathology showed improved diagnostic accuracy.

BACKGROUND: The aim of the International Academy of Cytology Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology is to improve cytology practice. This study assessed cytologic diagnoses made with the system and its efficacy when it was applied by pathologists with different levels of experience. METHODS: In all, 1080 cases of breast fine-needle aspiration biopsy (FNAB) over a period of 16 years were reviewed and reclassified with the system. The category distribution and the diagnostic performance were compared with the original diagnoses. The concordance rates for diagnoses from pathologists with different levels of experience were also determined. RESULTS: The distribution of cytologic diagnoses made with the system was as follows: 11.7% were insufficient, 56.6% were benign, 20.1% were atypical, 6.1% were suspicious for malignancy, and 5.6% were malignant. The rates for the insufficient and atypical categories were lower than the original diagnosis rates (13.1% and 23.8%, respectively). Overall, 120 cases (11.1%) were recategorized. Among those recategorized as benign, suspicious, or malignant with follow-up data, 96.7% were correctly reclassified. A significant improvement in diagnostic performance was found with the system (P < .001). Such improvement was also seen in problematic breast lesions, including fibroepithelial lesions, papillary lesions, and low-grade carcinomas. Pathologists with intermediate experience showed a higher concordance with an expert pathologist in the diagnoses than those with short experience (κ, 0.838 vs 0.634). CONCLUSIONS: The system effectively categorized the diagnoses, and the diagnostic performance of FNAB reporting was improved. The structured reporting also enhanced the reproducibility of reporting by pathologists with intermediate experience and, to some extent, those with short experience.

Accuracy of ultrasound in the characterisation of deep soft tissue masses: a prospective study.

PURPOSE: To investigate the accuracy of ultrasound in characterising the type of mass and likelihood of malignancy in deep soft tissue masses. METHODS: Five hundred seventy-nine deep soft tissue masses were prospectively studied by ultrasound. Masses (n = 137) with prior MRI or CT were not included. Following ultrasound examination, the likely nature of the mass as well as the confidence of the reporting radiologist ('fully confident' versus 'not fully confident') about the ultrasound diagnosis was recorded. Clinical and ultrasound diagnoses were compared with the histological diagnosis which was available in 134 (23%) of the 579 masses. RESULTS: Compared with histology, clinical and ultrasound accuracy for characterising the type of mass were 47% and 88% respectively when all differential diagnoses were considered. The radiologist was fully confident regarding the type of 436 (75%) of 579 masses and, in this setting, for those cases that could be compared with histology, diagnostic accuracy was 96%. For the remaining masses, where the radiologist was not fully confident, accuracy compared with histology was 58% for the first differential diagnosis and 80% for all differential diagnoses. For identifying malignancy, sensitivity, specificity, and positive and negative predictive value of ultrasound were 97%, 58%, 67%, and 99% respectively. Ultrasound alone was considered sufficient for diagnostic workup in over half of all deep soft tissue masses. CONCLUSION: Ultrasound is useful at characterising and recognising malignancy in deep soft tissue masses. Provided local practice patterns are favourable, ultrasound may be considered a first-line investigation in the diagnostic workup of deep soft tissue masses. KEY POINTS: • In three-quarters of cases, one can be fully confident about characterising the nature of deep soft tissue masses on ultrasound and, for those fully confident cases that could be compared with histology, the diagnostic accuracy of ultrasound was 96%. • Ultrasound can correctly recognise nearly all malignant deep soft tissue masses but some benign masses will also be considered possibly malignant. • Ultrasound alone was considered sufficient for imaging workup in over half of deep soft tissue masses.

Accuracy of ultrasound in the characterization of superficial soft tissue tumors: a prospective study.

OBJECTIVE: To prospectively evaluate the accuracy of ultrasound in defining the specific nature of superficial soft tissue masses as well as determining malignancy. MATERIALS AND METHOD: Eight hundred twenty-three superficial soft tissue masses were prospectively evaluated with ultrasound by one of five experienced musculoskeletal radiologists. The radiologist at the time of examination provided one to three specific differential diagnoses and the perceived level of confidence with regard to each diagnosis. Clinical and ultrasound diagnoses were compared with the histological diagnosis to determine accuracy. Tumor malignancy was determined by histology or clinical/imaging follow-up. RESULTS: Histological correlation was present for 219 (26.6%) of the 823 masses. Compared with histology, the accuracy of clinical and ultrasound examination for determining specific tumor type was 25.6% and 81.2% respectively considering all differential diagnoses provided. Radiologists were "fully confident" with the ultrasound diagnosis in 585 (71.1%) of 823 masses overall. In this setting, when compared with histology, the diagnostic accuracy of ultrasound was 95.5%. When the radiologist was "not fully confident," accuracy was 41.3% for the first differential diagnosis and 60.9% for all differential diagnoses. Diagnostic accuracy improved with increasing radiologist experience. Sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound for identifying malignant tumor were 93.3%, 97.9%, 45.2%, and 99.9% respectively. CONCLUSIONS: One can be "fully confident" at characterizing over two-thirds of superficial soft tissue masses based on ultrasound appearances and, in this setting, diagnostic accuracy is very high. Ultrasound examination is also highly accurate at discriminating benign from malignant superficial soft tissue masses.

A narrative review of gallbladder adenomyomatosis: what we need to know.

Gallbladder adenomyomatosis (GA) is increasingly encountered in clinical practice due to increasing use of imagings especially ultrasound (US). Clinicians need to know what is the implication of this condition and its proper management. GA is a degenerative and proliferative disease characterized by excessive epithelial proliferation associated with hypertrophy of muscularis propria. This leads to outpouchings of mucosa into or beyond the muscle layer forming intramural diverticula recognized as Rokitansky-Aschoff sinuses (RAS). Three types of GA are recognised: fundal, segmental and diffuse type. In fundal GA, there is focal thickening involving the GB fundus. In segmental GA, there is circumferential overgrowth of the GB wall that leads to formation of compartments. In diffuse GA, there is disseminated thickening and irregularity of the mucosa and muscularis. The pathogenesis of GA is unknown. It commonly occurs in middle age with equal sex distribution. Diagnosis of GA is by imagings showing thickened gallbladder wall containing cysts. Characteristic features are "comet-tail" artefacts and "twinkling" artefacts on US, "pearl-necklace sign" on magnetic resonance imaging (MRI) and "rosary sign" on computed tomography (CT). Cholecystectomy should be offered for symptomatic GA of any type. For asymptomatic GA, cholecystectomy may be considered for segmental type for its increased risk of malignancy and for diffuse type for its difficult visualization of any coexisting malignancy. Asymptomatic fundal GA can be safely observed with US. How frequent and how long should a fundal GA be monitored with US remains unknown. In case of diagnostic doubt, cholecystectomy should always be offered to avoid overlooked malignancy.

Thickness-to-Height Ratio of Intravesical Prostatic Protrusion Predicts the Clinical Outcome and Morbidity of Prostatic Artery Embolization for Benign Prostatic Hyperplasia.

PURPOSE: To evaluate the presence of intravesical prostatic protrusion (IPP) and its thickness-to-height (T/H) ratio as a predictor for the clinical outcome and morbidity of prostatic artery embolization (PAE) for benign prostatic hyperplasia. MATERIALS AND METHODS: This was a prospective, single-center, institutional review board-approved study from June 2015 to December 2018 of 82 consecutive patients (age, 53-79 years; median, 66 years) with International Prostate Symptom Score (IPSS) ≥15 and quality-of-life (QOL) score ≥3. The presence of IPP and its T/H ratio were assessed on baseline magnetic resonance imaging for their correlation with the clinical outcomes of suboptimal IPSS (IPSS ≥10) and suboptimal QOL (QOL ≥3) up to 12 months after PAE and the occurrence of post-procedure complications (≤30 days), which caused a certain degree of urinary outflow obstruction. The chi-squared test was used for analysis. RESULTS: IPP was present in 57 of 82 patients (69.5%). The presence of IPP correlated with the occurrence of post-procedure complications (P = .009) but not with suboptimal IPSS at 12 months (P = .758). IPP with a T/H ratio ≤1.3 correlated with suboptimal IPSS at 12 months (P = .025) and suboptimal QOL at 6 months (P = .025) and 12 months (P = .008), as well as with the occurrence of post-procedure complications (P = .009). CONCLUSIONS: IPP with a T/H ratio ≤1.3 predicted the occurrence of post-procedure complications with urinary obstruction. A T/H ratio ≤1.3 but not the presence of IPP alone predicted the clinical outcome up to 12 months after PAE.

Top-Ten Tips for Imaging the Triangular Fibrocartilaginous Complex.

The triangular fibrocartilage complex (TFCC) is a crucial structure for both maintaining the stability of the distal radioulnar joint (DRUJ) and acting as a cushion for axial loading of the ulnocarpal joint. Injury to the TFCC can lead to early degeneration of the DRUJ and ulnocarpal joint, with resultant chronic wrist pain and weakness. The TFCC is a moderately complex structure with several attachments to the adjacent bony and cartilaginous structures. Familiarity with the anatomy of the TFCC is a prerequisite for identification of TFCC tears. Several pitfalls can occur while assessing the TFCC on magnetic resonance imaging (MRI) if one is not familiar with the MRI appearances. This article illustrates key tips for diagnosing TFCC tears on MRI.

A Prospective Study to Monitor for Tuberculosis During Anti-tumour Necrosis Factor Therapy in Patients With Inflammatory Bowel Disease and Immune-mediated Inflammatory Diseases.

BACKGROUND: Biologic therapies have revolutionised the treatment of immune-mediated diseases including inflammatory bowel disease [IBD] and rheumatological disorders. However, biologic treatments are associated with an increased risk of reactivation of latent tuberculosis. Data from regular monitoring for latent tuberculosis infection [LTBI] during biologic treatment are lacking. METHODS: Consecutive patients eligible for biologic therapies were screened for LTBI and prospectively followed up for 3 years. Incidence and risk factors of latent tuberculosis tests conversion (interferon gamma release assays [IGRA], tuberculin skin tests [TST], and chest radiography [CXR]) with clinical outcomes were studied. RESULTS: A total of 108 patients [83 IBD; 25 rheumatological disorders] were included. At baseline, 18/108 [16.7%] patients [five IBD; 13 rheumatological disorders] were tested positive for LTBI. Of these, 14/18 [77.8%] patients received isoniazid monotherapy for 9 months. Of the remainder, 17/90 [18.9%] patients had LTBI test conversion while on biologic therapies and of these 14/17 [82.4%] received isoniazid monotherapy for 9 months. Age, sex, smoking status, alcohol use, travel history, disease type, and immunosuppressive therapy were not associated with LTBI test conversion. In subjects with IGRA conversion, serial IGRA levels normalised after completion of isoniazid except in one patient whose IGRA remained persistently elevated despite isoniazid and who subsequently developed active TB. CONCLUSIONS: Conversion of LTBI is common and occurred early during biologic therapy in an area with intermediate TB burden. Subjects with latent TB tests conversion and persistently high IGRA levels may have an increased risk of TB reactivation or development of active TB, and they require close observation or intensive workup for active TB.

Case-Control Study of Intra-arterial Verapamil for Intraprostatic Anastomoses to Extraprostatic Arteries in Prostatic Artery Embolization for Benign Prostatic Hypertrophy.

PURPOSE: It is hypothesized that intra-arterial administration of verapamil is a safe and effective way to reverse the flow in intraprostatic anastomoses to extraprostatic arteries without compromising treatment outcomes in prostatic artery embolization (PAE) for benign prostatic hypertrophy (BPH). MATERIALS AND METHODS: A prospective study of 62 prostate sides in 31 consecutive patients (median age, 66 y; range, 60-71 y) with symptomatic BPH was undertaken. Median prostate volume was 72.4 mL (range, 48.8-85.8 mL), median International Prostate Symptom Score was 21 (range, 15-23), and median urine peak flow rate was 4 mL/s (range, 2-6 mL/s). The arterial anastomoses were classified as types I-III according to vascular morphology. Treatment safety was assessed in terms of adverse events and complications, and treatment effectiveness was assessed in terms of success rate of angiographic flow reversal. RESULTS: The PAE procedure was successfully completed in all 31 patients (100%). Adverse events in both groups were transient and mild and did not necessitate prolonged hospitalization. There was no clinical evidence of any significant nontarget ischemic complication in either group. Intraprostatic anastomosis was diagnosed in 19 of 31 patients (61.3%) and 22 of 62 prostate sides (35.5%). Success rates of verapamil treatment were 88.9% overall (20 of 22) and 100% (19 of 19) in type II and III anastomoses. There was no difference between the treatment group and the control group in clinical, urologic, and imaging outcomes of PAE. CONCLUSIONS: Intra-arterial verapamil treatment was probably safe and effective in causing flow reversal in type II and III intraprostatic anastomoses and in preventing ischemic complications in PAE for BPH without compromising PAE outcomes.

Surgical Intervention for Primary Spontaneous Pneumothorax in Pediatric Population: When and Why?

INTRODUCTION: Spontaneous pneumothorax in pediatric patients is relatively uncommon. The management strategy varies in different centers due to dearth of evidence-based pediatric guidelines. In this study, we reviewed our experience of thoracoscopic management of primary spontaneous pneumothorax (PSP) in children and identified risk factors associated with postoperative air leakage and recurrence. MATERIALS AND METHODS: We performed a retrospective analysis of pediatric patients who had PSP and underwent surgical management in our institution between April 2008 and March 2015. Demographic data, radiological findings, interventions, and surgical outcomes were analyzed. RESULTS: A total of 92 patients with 110 thoracoscopic surgery for PSP were identified. The indications for surgery were failed nonoperative management with persistent air leakage in 32.7%, recurrent ipsilateral pneumothorax in 36.4%, first contralateral pneumothorax in 14.5%, bilateral pneumothorax in 10%, and significant hemopneumothorax in 5.5%. Bulla was identified in 101 thoracoscopy (91.8%) with stapled bullectomy performed. 14.5% patients had persistent postoperative air leakage and treated with reinsertion of thoracostomy tube and chemical pleurodesis. 17.3% patients had postoperative recurrence occurred at mean time of 11 months. Operation within 7 days of symptoms onset was associated with less postoperative air leakage (P = .04). Bilateral pneumothorax and those with abnormal radiographic features had significantly more postoperative air leakage (P = .002, P < .01 respectively) and recurrence (P < .01, P = .007). CONCLUSION: Early thoracoscopic mechanical pleurodesis and stapled bullectomy after thoracostomy tube insertion could be offered as a primary option for management of large PSP in pediatric population, since most of these patients had bulla identified as the culprit of the disease.

Prostate Artery Embolization for Complete Urinary Outflow Obstruction Due to Benign Prostatic Hypertrophy.

BACKGROUND: We aimed to evaluate the effectiveness of PAE in weaning of catheter and relieving obstructive urinary symptoms in patients with acute urinary retention (AUR) due to benign prostatic hypertrophy (BPH) and failed trial without catheter (TWOC). MATERIALS AND METHODS: In this prospective study approved by the institutional review board, a signed informed consent was obtained. Eighteen consecutive patients with AUR due to BPH and failed TWOC were recruited. Nineteen consecutive patients with BPH but without AUR were recruited as a control. Patients with CTA evidence of arterial occlusion or significant stenosis along the prostate artery access path were excluded. PAE was performed using microspheres (100-300 µm diameter). Outcome assessment included successful weaning of catheter in 2 weeks, procedure-related complications, change of symptomatology and urodynamic findings at 1 month as compared to baseline, percent non-perfused prostate volume, and prostate volume reduction on MRI at 2 weeks. RESULTS: Two patients in the study group and four in the control group were excluded due to arterial pathology. Embolization of bilateral prostate arteries was achieved in all patients in both the groups (100%). There was no complication. The catheter was successfully weaned in 87.5% (14/16) of patients within 14 days in the treatment group. There was no significant difference in patient demographics, prostate characteristics, and all outcome assessment parameters between both the groups. CONCLUSIONS: PAE was probably safe and effective in weaning of catheter and relieving obstructive urinary symptoms in patients due to BPH, with treatment outcomes comparable to those without AUR.

Diagnostic capability of low- versus high-field magnetic resonance imaging for lumbar degenerative disease.

STUDY DESIGN: Cohort study. OBJECTIVE: To investigate the diagnostic capability of low-field magnetic resonance imaging (MRI) compared with high-field MRI for degenerative disease of the lumbar spine. SUMMARY OF BACKGROUND DATA: Low-field MRI has several advantages over high-field magnetic resonance systems (easier installation, lower purchase, and maintenance cost). The diagnostic capability of low-field MRI for degenerative disease of the lumbar spine has not been compared with that of high-field MRI. METHODS: Hundred patients (mean age: 56.3 yr, range: 32-80; F:M = 59:41) with neurogenic claudication or sciatica were studied. All patients underwent MRI of the lumbar spine on both low-field (0.25T) and high-field (1.5T or 3.0T) magnetic resonance systems. Intervertebral disc herniation, central canal, lateral recess, and exit foraminal stenosis as well as nerve root compression at L3-L4, L4-L5, and L5-S1 were evaluated by 2 radiologists for both low- and high-field systems using established reliable grading systems. RESULTS: There was excellent agreement between low- and high- field MRI with regard to grading the presence and severity of disc herniation (r = 0.92-0.94; P < 0.05), central canal stenosis (r = 0.89-0.91; P < 0.05), lateral recess stenosis (r = 0.81-0.87; P < 0.05), and exit foramen stenosis (r = 0.81-0.89; P < 0.05). Descending or exiting nerve root compression occurred in 52% of patients at L3-L4, L4-L5, or L5-S1 levels, with good agreement between low-field and high-field MRI (r = 0.71-0.76; P < 0.05) for nerve root compression. CONCLUSION: Excellent reliability between low- and high- field MRI was found for most features of lumbar disc degeneration, with good agreement for nerve root compression. 0.25T MRI was more susceptible to motion artifact, probably due to longer scanning time. LEVEL OF EVIDENCE: 3.

Radiological diagnosis and management of idiopathic spontaneous intra-abdominal haemorrhage (abdominal apoplexy): a case series.

PURPOSE: Idiopathic spontaneous intraperitoneal haemorrhage (ISIH), historically known as abdominal apoplexy, is spontaneous haemorrhage due to rupture of an intra-abdominal visceral vessel in the absence of trauma or underlying pathology. It is an exceptionally rare condition, with mostly scattered case reports available. The aim of this study was to describe this rare condition, possible associated risk factors, and usefulness of multislice-CT (MS-CT) angiogram in its diagnosis prior to intervention. METHODS: A retrospective review of patients diagnosed with ISIH. Radiological records of haemoperitoneum from a single tertiary hospital in 2006-2013 were analysed, and the cases of ISIH were identified. Demographics (including pre-morbid hypertension status), abdominal aortic calcification as a measure of atherosclerotic changes, MS-CT angiogram +/- conventional digital subtraction angiograph images, surgical records and outcomes were reviewed. RESULTS: 425 cases of haemoperitoneum were retrieved from hospital radiology database from 2006 to 2013, and 5 patients (1.1%) diagnosed with ISIH were identified (4 males, 1 female, mean age of 64 years). 4 out of 5 patients (80%) had a history of hypertension (mean 150/90 mmHg) and 3 patients had moderate abdominal aortic atherosclerosis. MS-CT angiogram was able to diagnose the bleeding source in 4 out of 5 patients, while the bleeding source remained occult in the last patient even with both MS-CT and traditional DSA angiography. Patients who underwent either embolization or surgery had no further re-bleeding in clinical follow up, ranging from 5 to 8 years. CONCLUSIONS: Hypertension and abdominal aortic atherosclerosis appear to be associated risk factors for ISIH, and MS-CT angiogram has a high sensitivity in detecting the site of haemorrhage. An integrated angiographic and surgical approach is important in managing patients with ISIH.

Performance of interferon-gamma release assay for tuberculosis screening in inflammatory bowel disease patients.

BACKGROUND: Screening for latent tuberculosis (TB) is mandatory in inflammatory bowel disease (IBD) before starting anti-tumor necrosis factor therapy. Data on the utility of screening tests in populations with moderate background risk of TB are limited. This study aims to evaluate the performance of interferon-gamma release assay (IGRA) with QuantiFERON-TB Gold in IBD patients in a TB endemic region. METHODS: Two hundred sixty-eight consecutive adult IBD patients and 234 healthy controls were prospectively recruited. Detailed clinical history, chest x-ray findings, and IGRA results were documented for all individuals. The IGRA positive rates between IBD patients, with or without immunosuppressant, and healthy controls were compared. RESULTS: The IGRA result was positive in 21.9% of IBD patients and 19.2% of healthy controls (P = 0.535). IBD patients on immunosuppressive therapy had a significantly lower IGRA positive rate (13.0% versus 29.6%; P = 0.002) compared with immunosuppressant-naive IBD patients. This difference seemed to be most prominent for patients taking azathioprine (11.8% versus 27.3%, P = 0.006). CONCLUSIONS: IGRA results are negatively impacted by immunosuppressive therapy. Current guidelines suggesting TB screening before anti-tumor necrosis factor therapy may be inadequate in patients already on immunosuppressive drugs. Latent TB testing seems best performed before the initiation of immunosuppressive therapies in IBD patients.

Ketamine-related cholangiopathy: a retrospective study on clinical and imaging findings.

PURPOSE: Ketamine is a commonly abused recreational drug in Southeast Asia. There are emerging reports on ketamine abuse causing liver injury and biliary dilatation. This retrospective study aims to investigate the clinical and radiological features of this condition. METHODS: A retrospective search in the database of our institute was performed from January 2008 to February 2014 for patients who were ketamine abusers, with deranged liver function and/or epigastric pain, and had computed tomography of the abdomen or magnetic resonance cholangiopancreatography. Patient demographics, clinical data, and radiological findings were reviewed. RESULTS: Twenty-six patients (11 male and 15 female) were included in this study. Eighteen (69 %) patients had fusiform dilatation of the common bile ducts (CBDs) without evidence of intrinsic or extrinsic obstruction, and non-dilated intrahepatic ducts. The degree of CBD dilatation correlated with duration of abuse. In five patients who achieved abstinence, the CBD dilatation showed improvement. CONCLUSIONS: Ketamine-related cholangiopathy manifested as fusiform dilatation of the CBD without evidence of obstructive lesions. Severity of CBD dilatation appears to be correlated with the duration of ketamine, and the condition is potentially reversible in abstinent patients.

Ultrasound of musculoskeletal soft-tissue tumors superficial to the investing fascia.

OBJECTIVE: The objective of our study was to evaluate the diagnostic accuracy of ultrasound in assessing musculoskeletal soft-tissue tumors superficial to the investing fascia. MATERIALS AND METHODS: Seven hundred fourteen superficial soft-tissue tumors evaluated with ultrasound by two musculoskeletal radiologists were retrospectively reviewed. In all ultrasound reports, the reporting radiologists provided one, two, or three diagnoses depending on their perceived level of diagnostic certainty. Two hundred forty-seven tumors had subsequent histologic correlation, thus allowing the accuracy of the ultrasound diagnosis to be determined. Images of the lesions with a discordant ultrasound diagnosis and histologic diagnosis were reviewed, and the ultrasound features were further classified as concordant with the known histologic diagnosis, concordant with the known histologic diagnosis with atypical features present, or discordant with the known histologic diagnosis. Four hundred sixty-seven tumors without pathologic confirmation were followed up clinically. RESULTS: Overall the accuracy of ultrasound examination for assessing superficial soft-tissue masses was 79.0% when all differential diagnoses were considered and 77.0% when only the first differential diagnosis was considered. The sensitivity and specificity of the first ultrasound diagnosis were 95.2% and 94.3%, respectively, for lipoma; 73.0% and 97.7% for vascular malformation; 80.0% and 95.4% for epidermoid cyst; and 68.8% and 95.2% for nerve sheath tumor. Reduced observer awareness of specific tumor entities tended to contribute to underdiagnosis more than poor specificity of ultrasound findings. Most tumors (236/247, 96%) were benign. The sensitivity and specificity of ultrasound for identifying malignant superficial soft-tissue tumors was 94.1% and 99.7%, respectively. CONCLUSION: The diagnostic accuracy of ultrasound in the assessment of superficial musculoskeletal soft-tissue tumors is high and can be improved through increased radiologist awareness of less frequently encountered tumors. Ultrasound is accurate for differentiating benign from malignant superficial soft-tissue tumors.

Pitfalls in ultrasonography of soft tissue tumors.

Ultrasonography is increasingly the first-line investigation for the assessment of soft tissue masses. With increasing experience, most soft tissues masses, particularly superficial soft tissue masses, can be specifically labeled based on their ultrasonographic appearances. This diagnosis is based on a conundrum of clinical and ultrasonographic findings rather than resting on a single sign alone. One should try to minimize labeling the ultrasonographic appearances as "nonspecific" because this adds little to what is already known. Putting a specific label on a soft tissue mass such as a lipoma, nerve sheath tumor, or giant cell tumor of tendon sheath minimizes the need for percutaneous biopsy, greatly enhances clinical efficiency with regard to discussions on management and outcome, as well as immediately reduces patient anxiety with regard to the presence of malignancy. This article addresses the general approach to ultrasonography of soft issue masses, highlighting in particular the common pitfalls encountered in their diagnosis.