Diffusivity Measurements Differentiate Benign from Malignant Lesions in Patients with Peripheral Neuropathy or Plexopathy

BACKGROUND AND PURPOSE:Peripheral nerve disorders caused by benign and malignant primary nerve sheath tumors, infiltration or compression of nerves by metastatic disease, and postradiation neuritis demonstrate overlapping features on conventional MR imaging but require vastly different therapeutic approaches. We characterize and compare diffusivities of peripheral nerve lesions in patients undergoing MR neurography for peripheral neuropathy or brachial or lumbosacral plexopathy.MATERIALS AND METHODS:Twenty-three patients, referred for MR neurography at our institution between 2003 and 2009 for a peripheral mononeuropathy or brachial or lumbosacral plexopathy and whose examinations included DWI, received a definitive diagnosis, based on biopsy results or clinical and imaging follow-up, for a masslike or infiltrative peripheral nerve or plexus lesion suspicious for tumor. Mean ADC values were determined within each lesion and compared across 3 groups (benign lesions, malignant lesions, and postradiation changes).RESULTS:Both ANOVA and Kruskal-Wallis tests demonstrated a statistically significant difference in ADC values across the 3 groups (P = .000023, P = .00056, respectively). Post hoc pair-wise comparisons showed that the ADC within malignant tumors differed significantly from that within benign tumors and postradiation changes. ADC within benign tumors and postradiation changes did not differ significantly from each other.CONCLUSIONS:DWI may be highly effective for the differentiation of benign from malignant peripheral nerve masslike or infiltrative lesions.

Peripheral neuropathies can be divided into mononeuropathies, polyneuropathies, and plexopathies. Patients present with pain, sensory symptoms, and/or motor deficits in the distribution of a single peripheral nerve, multiple peripheral nerves, or a nerve plexus. Mononeuropathies affect a single peripheral nerve. Polyneuropathies affect multiple peripheral nerves. In plexopathies, symptoms are localized to the brachial or lumbosacral plexus.Polyneuropathies are generally attributable to systemic diseases (eg, diabetes and vitamin deficiencies), while mononeuropathies are most often due to trauma, nerve compression syndromes that occur at a few characteristic anatomic locations, or mass lesions. History and physical examination, supplemented in a subset of cases by laboratory studies, electrodiagnostic studies, and neuroimaging, are the main tools for diagnostic evaluation. In patients with a classic compression mononeuropathy, such as median nerve compression at the carpal tunnel, the diagnosis can often be made clinically and corroborated by needle electromyography, nerve conduction, and/or imaging studies.^1–4 For mononeuropathies involving nerves not typically susceptible to compression syndromes, imaging can play an essential role in identifying the lesion and guiding management.Plexopathies give rise to motor and/or sensory deficits in an extremity. Most brachial plexopathies (75%) are attributable to postradiation changes, primary and metastatic lung cancer, or metastatic breast cancer.⁵ Common causes of lumbosacral plexopathy are primary and metastatic tumor, including cervical, endometrial, ovarian, prostate, testicular, and colorectal cancer; postradiation changes; and diabetes.⁶ For patients with a history of radiation for malignancy, recurrent tumor with nerve invasion must be distinguished from radiation plexopathy; both can develop months to years following therapy and can have similar clinical presentations.⁶Although benign and malignant primary nerve sheath tumors, infiltration of nerves by metastatic disease, and postradiation neuritis require different therapeutic approaches, they also demonstrate overlapping features on MR imaging, including T2 hyperintensity, focal enlargement, and enhancement.^7,8 Diffusivity measurements from DWI may be helpful in differentiating distinct pathologic entities. In prior studies, DWI was useful in differentiating malignant and benign peripheral nerve sheath tumors,⁹ retroperitoneal masses,¹⁰ head and neck tumors,^11,12 and lymph nodes.^13,14 Other studies have demonstrated differences in the diffusivities of adult¹⁵ or pediatric brain tumors¹⁶ that correlate with tumor grade and/or histologic type. In this study, we focus on masslike or infiltrative lesions of the peripheral nerves detected by MR imaging in patients presenting clinically with a peripheral mononeuropathy or plexopathy. We characterize and compare the diffusivities of these lesions and demonstrate significant differences among benign and malignant peripheral nerve tumors and postradiation changes.     

Relationship between stress ankle radiographs and injured ligaments on MRI

Objective

This study was performed to investigate the relationship between the injured lateral ankle ligaments on MRI and stress ankle radiographs.

Materials and methods

Two hundred and twenty-nine consecutive patients (mean age 35.5 years, SD 14.6 years; 136 males and 93 females) that underwent ankle stress radiographs and MRI for lateral ankle instability were included. Tibiotalar tilt angle and anterior translation of talus were measured on stress ankle radiographs. Degree of lateral ligaments (anterior talofibular, calcaneofibular, and posterior talofibular) and deltoid ligament injuries were evaluated and scored as intact (0), partial injury (1), and complete injury (2) on MR images. Effusion of ankle joint was also recorded. The effects of gender, age, injuries of ligaments, and ankle joint effusion on stress radiographs were statistically analyzed.

Results

Gender (p?=?0.010), age (p?=?0.020), and anterior talofibular ligament (ATFL) injury (p?<?0.001) were the factors significantly affecting tibiotalar tilt angle. Posterior talofibular ligament (PTFL) injury (p?=?0.014) was found to be the only significant factor affecting the anterior translation on the anterior drawer radiographs.

Conclusions

ATFL injury and PTFL injury on MRI significantly affected tibiotalar tilt angle and anterior drawer on stress radiographs. Other factors, such as age and gender, need to be considered in evaluating radiographic lateral ankle instability.     

A minimally invasive method for creating coronary stenosis in a swine model for MRI and SPECT imaging

RATIONALE AND OBJECTIVES: To develop a less-invasive method for creating coronary stenosis in an animal model for the study of myocardial perfusion defects by using magnetic resonance imaging (MRI) and single-photon-emission computed tomography (SPECT). METHODS: Eleven farm pigs were instrumented with an MR-compatible coronary flow-reduction fitting in the left anterior descending coronary artery (LAD). These fittings were turned from a nylon rod, tapered from a maximum outer diameter of 3 mm, and drilled to a specified inner diameter (depending on the degree of coronary stenosis desired). The flow-reducing fittings were delivered over a coronary guidewire and advanced to a wedge position in the proximal LAD with an angioplasty catheter via a carotid artery approach. Perfusion determined by contrast-enhanced MRI at peak dipyridamole stress was compared with that obtained by 99mTc sestamibi SPECT. Radiolabeled microspheres were injected at rest, after stenosis implantation, and at peak pharmacological stress to establish the severity of the coronary lesion. RESULTS: Coronary stenosis was successfully created in seven animals. Mild coronary stenoses (<60%) were created in four animals. Significant coronary stenoses (80%-90%) were created in three animals. Thrombosis of the coronary flow-reducing fittings was observed in four animals, leading to sudden death in three animals and myocardial infarction in one animal. CONCLUSIONS: This method of angioplasty-guided, LAD coronary stenosis creation in a swine model presents a less-invasive alternative to open-chest techniques such as hydraulic occluders and ameroid constrictors.     

Randomized control trial comparing radiographic total knee arthroplasty implant placement using computer navigation versus conventional technique

The aim of this study is to assess the radiological outcome of conventional techniques versus computer-navigated surgery for total knee arthroplasty. Ninety patients with knee arthritis were prospectively randomized into 3 groups: conventional technique: extramedullary (EM) and intramedullary (IM) tibia guide versus computer navigation surgery (CAS). Two surgeons performed all procedures. Standardized long leg coronal and sagittal x-rays were evaluated by a blinded assessor. Our results showed that CAS had greater consistency and accuracy in implant placement. In the coronal view, 93.3% in the CAS group had better outcomes compared with EM (73.4%) and IM (60.0%). In the sagittal axis, 90.0% CAS also had better outcomes compared with EM (63.3%) and IM (76.7%). Computer-navigated total knee arthroplasty helps increase accuracy and reduce "outliers" for implant placement.     

A novel surgical correction through a small transverse incision for pectus excavatum

Surgical correction of pectus excavatum (PE) has been well established since Ravitch's publication in 1949. However, Ravitch's procedure, even if modified, was associated with the relatively radical nature of the operation. The aim of this study was to report our early experience and results in treatment of PE by a novel less invasive surgical technique through a small skin incision. From 1998 to 2003, a novel surgical correction through a small transverse incision was performed for 11 patients with PE, including 9 males and 2 females. The mean age was 9.2 years (range, 3 to 17 years). The less invasive surgical technique consisted of a small transverse skin incision over the deepest part of the PE deformity, subcutaneous dissection to the margin of the depressed deformity, elevation of pectoralis musculature from the midline toward the lateral border of the operative field, subperichondrial resection of the short segment (1 to 2 cm) of the involved costal cartilages, detachment of the xiphoid process and elevation of the sternum with sharp or blunt dissection, retrosternal titanium miniplate strutting, placement of drainage tubes in the mediastinum or pleural spaces, and closure of the operative wound. No sternal osteotomy was performed in this series. The average length of the skin incision was 3.2 cm. The number of the resected cartilages varied from 3 to 6 ribs on each side. The average blood loss was 41 mL (range, 10 to 80 mL), and the operation time was 3.1 hours. The duration of hospitalization was 4.4 days on average. There was no surgical complication or mortality. All patients were satisfied with their cosmesis, and no migration of the retrosternal strut was found in chest radiographs until the date of analysis. This less invasive surgical technique, which did not require osteotomy, could be effectively performed through a small skin incision and was associated with steady recovery of chest wall deformity, as well as excellent cosmetic results.     

Simultaneous pancreas-kidney transplantation from donation after cardiac death: successful long-term outcomes

OBJECTIVE: The outcomes of simultaneous pancreas-kidney (SPK) transplantation with donor organs procured from donation after cardiac death (DCD) are compared with transplants performed with donor organs recovered from donation after brain death (DBD). SUMMARY BACKGROUND DATA: Concerns exist regarding the utilization of pancreata obtained from DCD donors. While it is known that DCD kidneys will have a higher rate of DGF, long-term functional graft survival data for DCD pancreata have not been reported. METHODS: A retrospective review of all DCD SPK transplants performed at a single center was undertaken. RESULTS: Patient, pancreas, and kidney survival at 5 years were similar between DCD and DBD organs. Pancreas function and outcomes were indistinguishable between the 2 modes of procurement. As expected, the DCD kidneys had an elevated rate of DGF, which had no significant long-term clinical impact. CONCLUSION: SPK transplantation using selected DCD donors is a safe and viable method to expand the organ pool for transplantation.     

Herniated nucleus pulposus in isthmic spondylolisthesis: higher incidence of foraminal and extraforaminal types

Background  

The purpose of this study was to evaluate the pattern of disc herniation and to investigate the associated symptoms in cases of isthmic spondylolisthesis. It is well known that the pathogenesis of degenerative spondylolisthesis associates with disc degeneration, followed by facet laxity and ligamentum flavum hypertrophy, which result in severe spinal canal stenosis. But isthmic spondylolisthesis is known to have a different pathogenesis. In isthmic spondylolisthesis, pseudodisc bulging is easily identified, and canal stenosis is comparatively rare. Therefore, we propose that isthmic spondylolisthesis has a different pattern of disc herniation from degenerative spondylolisthesis. We studied the type, incidence of disc herniation and clinical symptoms related to isthmic spondylolisthesis.     

Burden of blood transmitted infections in substance users admitted for inpatient treatment in Singapore and the associated factors

INTRODUCTION

There is a paucity of local data on the prevalence of blood transmitted infections (BTIs), such as hepatitis B, hepatitis C and human immunodeficiency virus (HIV) infections, among illicit drug users. This study aimed to examine the prevalence of BTIs among substance-dependent inpatients and identify the factors associated with BTIs.

METHODS

We conducted a retrospective case note analysis of 170 inpatients who had a history of substance dependence and were seen at the National Addictions Management Service, Singapore, between 1 June 2009 and 31 May 2010.

RESULTS

The majority of the 170 inpatients were male (88.2%) and Chinese (58.2%). The mean age of the patients was 43.1 years, and the main drug of abuse was opioids (86.5%). BTIs were found in 70 (41.2%) inpatients; the prevalence of hepatitis B, hepatitis C and HIV infections was 3.7%, 39.6% and 0%, respectively. Lifetime intravenous drug use, but not needle-sharing, was more common among inpatients who were positive for BTIs (p < 0.01). Logistic regression analysis showed that lifetime intravenous drug use (OR 4.3, 95% CI 1.7–10.8, p < 0.01) was the only significant predictor of BTI.

CONCLUSION

41.2% of the substance users seeking help were positive for at least one BTI. Lifetime intravenous drug users were found to be more than four times more likely to have a BTI. Early detection and prevention is essential to improve prognosis.     

Previous portal hypertension surgery negatively affects results of mesenteric to left portal vein bypass

Purpose

The mesenteric to left portal vein bypass (MLPVB) has been successfully used to treat extrahepatic portal vein obstruction (EHPVO) in children. We examined the effect of failed prior surgical or radiological procedures intended to treat complications of portal hypertension on the success rate of subsequent MLPVB surgery.

Methods

Sixty-two patients younger than 18 years with EHPVO underwent MLPVB between 1997 and 2006. Children were divided into 3 groups: those with no prior surgery related to portal hypertension, those with prior portosystemic shunts, and those with either splenectomy or mesenteric vascular embolization procedures. The effect of prior procedures on the patency rate of the MLPVB was then examined.

Results

Of 62 children, 11 (17.7%) had significant procedures to treat symptoms of portal hypertension: 6 had at least 1 portosystemic shunt attempt, 3 had isolated splenectomy, and 2 had embolization of the splenic artery or coronary and peripancreatic varices. Patients with previous portal hypertension surgery were significantly older and larger than those with no surgery. Patients with no prior interventions had a significantly higher MLPVB patency rate (88.2%, 45/51) than those with no prior interventions (63.6%, 7/11). Prior splenectomy alone was not found to adversely affect MLPVB. Patients with prior embolization procedures or unsuccessful shunts had significantly poorer successful outcomes (0% and 66.7%) than those with no prior interventions (88.2%; P < .005).

Conclusions

The results demonstrate that prior portosystemic shunts or mesenteric embolizations have a deleterious effect on outcome after MLPVB and should be avoided whenever possible. This study suggests that patients with symptomatic EHPVO should undergo MLPVB as a primary intervention rather than as a rescue procedure to optimize MLPVB patency.