Dysembryoplastic neuroepithelial tumors: proton MR spectroscopy,diffusion and perfusion characteristics

Introduction We describe the magnetic resonance (MR) imaging characteristics of dysembryoplastic neuroepithelial tumors (DNT) and discuss their differential diagnosis. Material and methods Proton MR spectroscopy (TE 30 and 136 ms), diffusion-weighted and perfusion images were retrospectively evaluated in 22 patients with pathologically proven DNT (17 male and 5 female, mean age 18.7 years) and 14 control subjects (10 male and 4 female, mean age 16.9 years). The results from the DNT patients and from the control subjects were compared using an independent sample t-test and the degree of correlation was tested by Pearson’s correlation. Results All DNTs were solitary and in a supratentorial cortical or subcortical location (ten temporal, eight frontal and four parietal). They had low-signal on T1-weighted images and high-signal on T2-weighted images without a prominent mass effect. Additionally a cystic appearance (six patients, 27.3%), cortical dysplasia (six patients, 27.3%) and contrast enhancement (four patients, 18.2%) were also noted. No significant differences were detected in NAA/Cho, NAA/Cr, NAA/Cho+Cr or Cho/Cr ratios between DNT and normal brain. DNTs had a significantly higher mI/Cr ratio and apparent diffusion coefficient (ADC) values and lower cerebral blood values than normal parenchyma (P < 0.001). ADC had the highest correlation with the diagnosis of DNT (r = 0.996) followed by relative cerebral blood volume (rCBV) (r = −0.883) and mI/Cr ratio (r = 0.663). Conclusion Proton MR spectroscopy, diffusion-weighted and perfusion imaging characteristics of DNTs provide additional information to their MR imaging findings. The MR spectrum showing a slight increase in mI/Cr ratio, and higher ADC and lower rCBV values than normal parenchyma help to differentiate DNTs from other cortical tumors, which had higher rCBV and lower ADC values than DNTs. This work was presented at the ASNR 45th Annual Meeting 2007.     

Impact of scanning direction on heart rate at certain levels of heart in electrocardiogram-gated 16-multidetector computed tomography angiography of coronary artery bypass grafts

OBJECTIVE: To assess impact of scanning direction on heart rates at certain levels of heart in electrocardiogram-gated 16-multidetector computed tomography (MDCT) detection of coronary artery bypass grafts and native coronary arteries. METHODS: Ninety patients with 219 grafts were studied by 16-MDCT. Forty-five patients were scanned craniocaudally. The remaining 45 patients were scanned caudocranially. Heart rates at each level were noted and compared between the 2 groups. RESULTS: The difference between mean heart rates of craniocaudal and caudocranial groups was found to be statistically significant at midcardiac, internal mammary artery origin, and cardiac base levels (P < 0.05). For the remaining levels, there was no statistically significant difference in mean heart rates. CONCLUSIONS: Performing electrocardiogram-gated 16-MDCT angiography for the evaluation of coronary arteries and bypass grafts in caudocranial direction provides lower heart rate at midcardiac and cardiac base levels of the heart, which are more prone to motion artifacts.     

Chronic inflammatory demyelinating polyradiculoneuropathy associated intracranial hypertension

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated demyelinating neuropathy. In this report, we detail the course of a 58-year-old male patient who had headache and double vision followed by progressive paresthesia and difficulty in walking. The patient had bilateral papilledema and mild leg weakness, absent ankle jerks and loss of sensation in distal parts of his lower and upper extremities. His electromyography (EMG) was concordant with CIDP and lumbar puncture revealed high opening pressure. The polyradiculoneuropathy as well as the papilledema and elevated cerebrospinal fluid (CSF) pressure improved under steroids. The improvement in intracranial hypertension (IHT) and papilledema under steroid treatment suggests that the IHT in this patient might be associated with CIDP.     

Effects of dextran-40 on flap viability after modified radical mastectomy

BACKGROUND:

Postoperative management of patients after modified radical mastectomy has evolved over the past decades. In the early postoperative period, wound complication rates were reported to be as high as 60%. Flap necrosis after modified radical mastectomy is a common problem encountered by surgeons. Various treatment strategies have been proposed in the literature but none have addressed the use of dextran-40.

OBJECTIVE:

To determine whether dextran-40 infusion improves skin flap viability after modified radical mastectomy.

METHODS:

Twenty-eight patients who underwent modified radical mastectomy were randomly assigned to receive dextran-40 or no dextran-40 intraoperatively after flap dissection. Patients were followed prospectively over a five-year period in a community hospital. The incidence of postmastectomy skin flap necrosis and prognosis of the necrotic area after dextran-40 infusion was observed.

RESULTS:

Flap necrosis was observed in five (17.8%) patients. Hypertension and diabetes mellitus were found to be risk factors for the development of flap necrosis (P<0.05). Flap thickness and tension on the flaps were found to be related to flap necrosis. Six of seven patients with flap perfusion problems (ecchymosis or necrosis) underwent dextran-40 treatment and healed without graft replacement.

CONCLUSIONS:

Dextran-40 treatment did not affect development of flap necrosis. However, if necrosis had already developed, the necrotic area of the skin flaps improved with dextran-40 treatment.     

Effects of different surface treatments on shear bond strength in two different ceramic systems

The purpose of this study was to evaluate the influence of different surface treatments (sandblasting, acid etching, and laser irradiation) on the shear bond strength of lithium disilicate-based core (IPS Empress 2) and feldspathic ceramics (VITA VM 9). One hundred ceramic discs were divided into two groups of 50 discs each for two ceramic systems: IPS Empress 2 (group I) and VITA VM 9 (group II). Each of the two groups was further divided into five surface treatment groups (ten each) as follows: group SB, sandblasting with alumina particles (50 μm); group HF, 5 % hydrofluoric acid etching; group L, Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10 W; manually, noncontact R14 handpiece); group SB–L, sandblasting + Er:YAG laser; and group HF–L, 5 % hydrofluoric acid + Er:YAG laser. Luting cement (Panavia 2.0) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, a shear bond strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with a two-way analysis of variance (ANOVA) and Tukey's honestly significant difference tests (α?=?0.05). The two-way ANOVA indicated that the shear bond strength was significantly affected by the surface treatment methods (p?<?0.05), but there was no significant interaction between the ceramic systems. Group SB–L had the highest mean values for each ceramic system. Sandblasting, followed by Er:YAG laser irradiation, enhanced the bond strength, indicating its potential use as an alternative method. The atomic force microscopic evaluation revealed that group SB had the most distinct sharp peaks among the groups.     

Documenting the location of prostate biopsies with image fusion

Study Type – Diagnostic (exploratory cohort)
Level of Evidence 2b What’s known on the subject? and What does the study add? Currently, systematic prostate biopsies are obtained with minimal information about their actual location. This study demonstrates that a electromagnetically tracked ultrasound probe can be used to guide biopsies into specific areas of the prostate. By registering the ultrasound to an MRI scan of the prostate, obtained prior to biopsy, it is possible to accurately map the location of biopsies. Thus, if a patient requires a repeat biopsy, or there is a question about whether a specific area of the prostate was sampled, this system can be used to more accurately guide biopsies in the future. OBJECTIVE To develop a system that documents the location of transrectal ultrasonography (TRUS)‐guided prostate biopsies by fusing them to MRI scans obtained prior to biopsy, as the actual location of prostate biopsies is rarely known. PATIENTS AND METHODS Fifty patients (median age 61) with a median prostate‐specific antigen (PSA) of 5.8 ng/ml underwent 3T endorectal coil MRI prior to biopsy. 3D TRUS images were obtained just prior to standard TRUS‐guided 12‐core sextant biopsies wherein an electromagnetic positioning device was attached to the needle guide and TRUS probe in order to track the position of each needle pass. The 3D‐TRUS image documenting the location of each biopsy was fused electronically to the T2‐weighted MRI. Each biopsy needle track was marked on the TRUS images and these were then transposed onto the MRI. Each biopsy site was classified pathologically as positive or negative for cancer and the Gleason score was determined. RESULTS The location of all (n= 605) needle biopsy tracks was successfully documented on the T2‐weighted (T2W) MRI. Among 50 patients, 20 had 56 positive cores. At the sites of biopsy, T2W signal was considered ‘positive’ for cancer (i.e. low in signal intensity) in 34 of 56 sites. CONCLUSION It is feasible to document the location of TRUS‐guided prostate biopsies on pre‐procedure MRI by fusing the pre‐procedure TRUS to an endorectal coil MRI using electromagnetic needle tracking. This procedure may be useful in documenting the location of prior biopsies, improving quality control and thereby avoiding under‐sampling of the prostate as well as directing subsequent biopsies to regions of the prostate not previously sampled.     

Comparative study of the closed reduction percutaneous cannulated screw fixation and open reduction palmar locking plate fixation in the treatment of AO type A2 distal radius fractures

Introduction

The present study was designed to demonstrate the efficacy of standard 4.0 mm cannulated screw fixation by comparing it with palmar locking plate fixation in the treatment of acute, unstable, simple extra-articular distal radius fractures.

Materials and methods

We prospectively collected and retrospectively analyzed outcomes data for 65 patients aged between 18 and 60 with AO type A2 fractures treated with closed reduction, percutaneous cannulated screw fixation (CRPCS n = 34) or open reduction palmar locking plate fixation (ORPLP n = 31). Range of motion, grip strength, Gartland–Werley and QuickDASH scores were compared at 2 months after surgery, and final follow-up (mean 32 months, range 12–90). Deterioration in radiographic parameters were measured and compared. Operative time and return to preinjury activity were evaluated.

Results

Parameters did not differ significantly between the groups at either time point with respect to grip strength or range of motion, except pronation and supination; they were better in the CRPCS group (p = 0.005 and 0.025, respectively) at 2 month follow-up. The Gartland–Werley and QuickDASH scores obtained at final follow-up were similar for each group and lacked statistical significance. Group comparison for the deterioration of radiologic parameters showed no significant difference. CRPCS group had significantly shorter operative time (p = 0.001) and there was no significant differences between the groups regarding the return to preinjury activity (p = 0.129).

Conclusions

CRPCS group was found to be as successful as ORPLP group and it may be suitable in the case of young, active individuals with AO type A2 distal radius fractures.     

Ruling out clinically significant prostate cancer with negative multi-parametric MRI

Purpose

To evaluate the negative predictive value (NPV) of a negative prostate multi-parametric magnetic resonance imaging (mpMRI) in ruling out clinically significant prostate upon 12-core systematic biopsy.

Methods

We retrospectively reviewed 114 men evaluated at our institution who underwent systematic 12-core biopsy within 1 year of a negative prostate mpMRI. Clinicopathologic features were evaluated and NPV was calculated for detection of clinically significant (Gleason ≥ 7) cancer. Regression analysis was performed to identify clinical predictors of biopsy outcome.

Results

Overall, 88 (77.2%) patients in our cohort had no cancer detected upon biopsy. The highest pathologic grade was Gleason 6 (3 + 3) in 22 (19.3%) patients, and Gleason ≥ 7 in 4 (3.6%) patients. NPV for detecting Gleason ≥ 7 cancer was 96.5% (95% CI 93.1–99.9%) in the entire negative MRI cohort, 100% in those who were prostate biopsy naïve (n = 20), 100% in those with a prior negative biopsy (n = 53), and 90% in those who have had a previous positive biopsy and on active surveillance (n = 41). Regression analysis identified no predictors of significant cancer in our cohort.

Conclusion

In our cohort of men with no lesions detected on prostate mpMRI, we found very low rates of clinically significant cancer on systematic 12-core biopsy. In the few patients who diagnosed with prostate cancer, the majority had low-risk disease and could remain on active surveillance. Although validation studies and greater sample size is needed before clinical recommendations can be made, our data suggest patients with negative mpMRI evaluated by experienced radiologists may avoid unnecessary prostate biopsy and potential overtreatment.