Dynamic 4D MRI for Characterization of Parathyroid Adenomas: Multiparametric Analysis

BACKGROUND AND PURPOSE:The hypervascular nature of parathyroid adenomas can be explored by proper dynamic imaging to narrow the target lesions for surgical exploration. The purpose of this study was to establish MR perfusion characteristics of parathyroid adenomas to differentiate them from their mimics, such as subjacent thyroid tissue and cervical lymph nodes.MATERIALS AND METHODS:Preoperative high-spatial and -temporal resolution dynamic 4D contrast-enhanced MR imaging in 30 patients with surgically proved parathyroid adenomas was evaluated retrospectively. Using coregistered images, we placed ROIs over the parathyroid adenoma, thyroid gland, and a cervical lymph node (jugulodigastric) to obtain peak enhancement, time-to-peak, wash-in, and washout in each patient. Data were analyzed by logistic regression and analysis of variance. Receiver operating characteristic analysis was performed to determine the optimal parameters for determination of parathyroid adenomas versus thyroid tissue and cervical lymph nodes.RESULTS:Parathyroid adenomas showed significantly (P < .05) faster time-to-peak, higher wash-in, and higher washout compared with cervical lymph nodes and significantly (P < .05) higher peak enhancement, faster time-to-peak, higher wash-in, and higher washout compared with thyroid tissue. Logistic regression analysis indicated significant contribution from time-to-peak (P = .02), wash-in (P = .03), and washout (P = .008) for differentiation of parathyroid adenomas from thyroid and cervical lymph nodes. Using receiver operating characteristic analysis, we obtained the best diagnostic accuracy from a combination of time-to-peak/wash-in/washout in the differentiation of parathyroid adenomas versus lymph nodes (area under the curve, 0.96; sensitivity/specificity, 88%/90%) and in distinguishing parathyroid adenomas versus thyroid tissue (area under the curve, 0.96; sensitivity/specificity, 91%/95%).CONCLUSIONS:Dynamic 4D contrast-enhanced MR imaging can be used to exploit the hypervascular nature of parathyroid adenomas. Multiparametric MR perfusion can distinguish parathyroid adenomas from subjacent thyroid tissue or lymph nodes with diagnostic accuracies of 96%.

Single parathyroid adenoma (PTA) is the most common cause of primary hyperparathyroidism, accounting for approximately 80%–90% of all cases.¹ Definitive treatment requires surgical excision, and preoperative localization with imaging is commonly used to decrease the size of surgical incisions and complication rates.²Imaging has been increasingly used for preoperative detection of parathyroid adenomas. While sonography and technetium Tc99m sestamibi scintigraphy have often been used as first-line imaging to localize PTA, these tests are often inconclusive. This situation has led to the development of multiphasic CT (4D CT), which identifies PTAs through their hypervascular perfusion pattern compared with lymph nodes and the thyroid gland. 4D CT has shown superior accuracy compared with scintigraphy,³ though the radiation dose remains as high as 5.56–10.4 mSv.^4–6MR imaging is an attractive alternative to both scintigraphy and 4D CT due to the lack of radiation and has been used for the evaluation of PTAs with some success,^7–9 though not with the same effectiveness as 4D CT. Traditional technical limitations to localizing PTAs with MR imaging have recently been addressed with modern MR imaging technology. These include limited spatial and temporal resolution for multiphase dynamic contrast-enhanced MR imaging over a large FOV required for parathyroid imaging. This limitation can be addressed by the use of fast imaging tools such as time-resolved imaging with stochastic trajectories (TWIST)¹⁰ and improved parallel imaging techniques such as controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA).¹¹ The second limitation is inhomogeneity of fat suppression in the neck required for detection of small parathyroid adenomas. The Dixon fat-suppression technique¹² can dramatically improve this shortcoming.¹³In this study by using a modified dynamic contrast-enhanced sequence with incorporation of a TWIST-CAIPIRINHA combination and the Dixon fat saturation technique, we sought to describe MR perfusion characteristics of PTAs in a cohort of patients with pathology-proved PTA. We hypothesized that MR perfusion biomarkers can differentiate PTA from PTA mimics, such as subjacent thyroid gland and cervical lymph nodes.     

Prediction of Gleason score upgrading in low-risk prostate cancers diagnosed via multi (≥12)-core prostate biopsy

Objectives  A paucity of data exists on actual pathology of the contemporary patients strictly categorized as having low-risk prostate cancer. We tried to identify useful preoperative predictors of Gleason score upgrading in patients who underwent radical retropubic prostatectomy (RRP) for low-risk prostate cancer diagnosed via multi-core prostate biopsy. Methods  A total of 203 patients who underwent radical RRP for low-risk prostate cancer, as defined by D’Amico et al.'s classification (clinical stage ≤T2a, biopsy Gleason sum ≤6, and PSA ≤10 ng/ml), detected via multi (≥12)-core prostate biopsy were enrolled. We reviewed patients preoperative and pathological data. Results  Among all subjects, 81 (39.9%) were upgraded to Gleason score ≥7 after RRP, whereas no downgrading was observed. In multivariate analysis, only preoperative PSA level (P = 0.024) and number of positive cores (P = 0.027) were observed to be independent predictors of Gleason score upgrading following RRP. Also, Gleason core upgrading was observed to be significantly associated with extraprostatic extension of tumor (P < 0.001) and positive surgical margin (P = 0.002). Conclusions  A significant proportion of patients with low-risk prostate cancer as defined by D’Amico et al.’s classification diagnosed via multi-core prostate biopsy in contemporary period may have Gleason score upgrading following RRP. For patients with low-risk prostate cancer, preoperative PSA level and number of positive cores may be useful predictors of Gleason score upgrading, which was observed to significantly associated with other adverse pathologic features.     

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.     

Open reduction of a chronic proximal dislocation after total hip arthroplasty

We report an unusual case of a chronic prosthetic dislocation that was caused by the buttonholing of a prosthetic femoral head by anterior soft tissue, which impeded reduction. A surprisingly good functional result was achieved by an open reduction and revision operation on a 56-year-old man, who had a chronic dislocation of a total hip prosthesis. Successful treatment with open reduction of a chronic proximal dislocation after total hip arthroplasty has not been reported previously in the literature.     

Treatment of Acne Scars and Wrinkles in Asian Patients Using Carbon-Dioxide Fractional Laser Resurfacing: Its Effects on Skin Biophysical Profiles

Background

Although ablative fractional resurfacing is known to be effective against photoaging and acne scars, studies on its efficacy, safety and changes in the skin characteristics of Asians are limited.

Objective

The aim of this study is to assess the efficacy and safety of carbon dioxide fractional laser (CO₂FL) in Koreans treated for wrinkles and acne scars, and to define the changes in skin characteristics during recovery period.

Methods

We administered one session of CO₂FL on 10 acne scar patients and 14 wrinkles patients with skin types IV and V. The surveillance of efficacy and side effects along with the measurement of biophysical properties was carried out before 1 day, 1 week, 1 month and 3 months after treatment.

Results

Using a non-invasive method, skin barrier damage, erythema and bronzing of skin during the recovery period were assessed, and all of the items eventually returned to the pre-treatment level. Skin elasticity was measured in the wrinkle group, and the statistically significant effect was sustained throughout the next three months. The outcome of treatment was found to be better than ''moderate improvement'' in both the acne scar and wrinkle groups. Further, there were no serious side effects three months post-procedure.

Conclusion

CO₂ FL is thought to be an effective and safe method for treating moderate to severe acne scars and wrinkles in Asians.     

Role of protein kinase C delta in X-ray-induced apoptosis of keratinocyte

Abstract:  In this study, we investigated the process of X-ray-induced apoptosis of skin keratinocyte, and the functional role of protein kinase C delta (PKCδ) and downstream signalling cascade. High-dose X-ray irradiation (10 Gy) led to the apoptosis of HaCaT keratinocyte, accompanied by PKCδ cleavage. Treatment with PKCδ inhibitor and adenoviral transduction of dominant-negative PKCδ clearly inhibited the X-ray-induced apoptosis of keratinocyte. In addition, X-ray induced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) and inhibition by ERK1/2 inhibitor abrogated the X-ray-induced apoptosis. Interestingly, overexpression of dominant-negative PKCδ markedly blocked the X-ray-induced phosphorylation of ERK1/2, suggesting that ERK1/2 is the functional downstream effector of PKCδ. Next, we investigated the difference between UVB and X-ray response. UVB induced the apoptosis of keratinocyte in a PKCδ-dependent manner, similar to X-ray response. However, UVB irradiation induced the phosphorylation of c-jun N-terminal kinases (JNK) and inhibition of JNK significantly protected the UVB-induced apoptosis. These results demonstrate that PKCδ is a key regulator in X-ray-induced apoptosis of keratinocyte and suggest that there is subtle difference in downstream signalling cascade between UVB and X-ray response of keratinocyte.     

Comparison of Nested PCR and RFLP for Identification and Classification of Malassezia Yeasts from Healthy Human Skin

Background

Malassezia yeasts are normal flora of the skin found in 75~98% of healthy subjects. The accurate identification of the Malassezia species is important for determining the pathogenesis of the Malassezia yeasts with regard to various skin diseases such as Malassezia folliculitis, seborrheic dermatitis, and atopic dermatitis.

Objective

This research was conducted to determine a more accurate and rapid molecular test for the identification and classification of Malassezia yeasts.

Methods

We compared the accuracy and efficacy of restriction fragment length polymorphism (RFLP) and the nested polymerase chain reaction (PCR) for the identification of Malassezia yeasts.

Results

Although both methods demonstrated rapid and reliable results with regard to identification, the nested PCR method was faster. However, 7 different Malassezia species (1.2%) were identified by the nested PCR compared to the RFLP method.

Conclusion

Our results show that RFLP method was relatively more accurate and reliable for the detection of various Malassezia species compared to the nested PCR. But, in the aspect of simplicity and time saving, the latter method has its own advantages. In addition, the 26S rDNA, which was targeted in this study, contains highly conserved base sequences and enough sequence variation for inter-species identification of Malassezia yeasts.     

Myeloid differentiation factor 88 regulates basal and UV-induced expressions of IL-6 and MMP-1 in human epidermal keratinocytes

Myeloid differentiation factor 88 (MyD88) is known as an adaptor protein for the Toll-like receptor (TLR) family and participates in signal transduction by binding to the cytoplasmic Toll/IL-1 receptor (TIR) domains of activated TLR. In this study, we demonstrated that expression of MyD88 is increased in photoaged skin compared with intrinsic aged human skin of the same elderly individuals, and that acute UV irradiation increases MyD88 expression in human skin in vivo. To investigate the effects of these high levels of MyD88 in photoaged skin and acutely UV-irradiated skin, human epidermal keratinocytes were infected with adenovirus expressing wild-type (MyD88wt), dominant-positive (MyD88DeltaC), and dominant-negative (MyD88DeltaN) MyD88 forms. Overexpression of MyD88wt and MyD88DeltaC, but not of MyD88DeltaN, increased the basal expressions of IL-6 and matrix metalloproteinase-1 (MMP-1) in human epidermal keratinocytes. Moreover, overexpression of MyD88DeltaN prevented UV-induced expressions of IL-6 and MMP-1 by inhibiting UV-induced activation of NF-kappaB and activating protein-1. These results suggest that MyD88 is important in IL-6 and MMP-1 expressions in both acutely UV-irradiated skin and in chronically sun-exposed human skin.     

Utilization of Ultrasonography in Dermatology: Two Case Reports of Calcinosis Cutis

Development of newer generation of cost-effective ultrasonic devices in recent years has increased the use of ultrasonography in dermatology. Several lesions can be diagnosed and managed using ultrasonography. Calcinosis cutis involves the deposition of insoluble calcium salts in the cutaneous and subcutaneous tissues. On ultrasonography, it specifically presents as hyperechoic deposits with a posterior acoustic shadowing artifact due to the acoustic properties of calcium. A 62-year-old female patient presented with a solitary, skin-colored, palpable nodule on the inner side of the right lower leg. The lesion was beneath the intact skin and detectable only on palpation. However, ultrasonography demonstrated a clear delineation of the lesion, showing hyperechoic deposits with a posterior acoustic shadow (15 MHz, linear probe). Skin biopsy and curettage were performed, revealing histological features consistent with calcinosis cutis. Four weeks after the procedure, ultrasonography performed to evaluate the outcome of treatment, showed recurrence. Another 18-year-old female patient presented with a skin-colored deep-seated nodule on the left temple. On ultrasonography, linear hyperechoic deposits with a posterior acoustic shadow were visible. Skin biopsy was performed, and histopathologic features showed calcified material in the subcutaneous tissue. These two cases of calcinosis cutis highlight the diagnostic value of ultrasonography in dermatology.     

Effect of trapping vascular endothelial growth factor-A in a murine model of dry eye with inflammatory neovascularization

AIM: To evaluate whether trapping vascular endothelial growth factor A (VEGF-A) would suppress angiogenesis and inflammation in dry eye corneas in a murine corneal suture model. METHODS: We established two groups of animals, one with non-dry eyes and the other with induced dry eyes. In both groups, a corneal suture model was used to induce inflammation and neovascularization. Each of two groups was again divided into three subgroups according to the treatment; subgroup I (aflibercept), subgroup II (dexamethasone) and subgroup III (phosphate buffered saline, PBS). Corneas were harvested and immunohistochemical staining was performed to compare the extents of neovascularization and CD11b+ cell infiltration. Real-time polymerase chain reaction was performed to quantify the expression of inflammatory cytokines and VEGF-A in the corneas. RESULTS: Trapping VEGF-A with aflibercept resulted in significantly decreased angiogenesis and inflammation compared with the dexamethasone and PBS treatments in the dry eye corneas (all P<0.05), but with no such effects in non-dry eyes. The anti-inflammatory and anti-angiogenic effects of VEGF-A trapping were stronger than those of dexamethasone in both dry eye and non-dry eye corneas (all P<0.05). The levels of RNA expression of VEGF-A, TNF-alpha, and IL-6 in the aflibercept subgroup were significantly decreased compared with those in the PBS subgroup in the dry eye group. CONCLUSION: Compared with non-dry eye corneas, dry eye corneas have greater amounts of inflammation and neovascularization and also have a more robust response to anti-inflammatory and anti-angiogenic agents after ocular surface surgery. Trapping VEGF-A is effective in decreasing both angiogenesis and inflammation in dry eye corneas after ocular surface surgery.