Multislice B₁ Mapping Method Using Magnetic Resonance Composite Spin Echo Sequences and Simultaneous Echo Refocusing

Radiofrequency (RF) transmit field (B1) mapping is a promising method in mitigating the B1 inhomogeneity in various magnetic resonance imaging (MRI) applications. Although several phase- or magnitude-based B1 mapping methods have been proposed, these methods often require complex modeling, long acquisition time, or specialized MRI sequences. A recently introduced simultaneous echo refocusing (SER) technique can be applied in the B1 mapping method to extend the three-dimensional (3D) spatial coverage only without long data acquisition. Therefore, in this study, a multislice B1 mapping method using composite spin echo sequences and SER techniques is proposed to obtain more accurate B1 mapping with short data acquisition time. To evaluate the performance of the proposed B1 mapping method, computational simulations were performed and compared with Morrell’s method, double angle method, and Yarnykh’s method. These results showed that the angle-to-noise ratio of the proposed B1 mapping method has wider B1 range compared to that of other B1 mapping methods. In addition, the proposed B1 mapping methods were compared to the multislice iterative signal intensity mapping method in both phantom and in vivo human experiments, and there was no remarkable difference between the two methods regarding the flip angle distribution in these experiments. Based on these results, this study demonstrated that the proposed B1 mapping method is suitable for accurately measuring B1 propagation under the condition providing reduced scan time and wider 3D coverage of B1 mapping by applying composite RF pulse and SER techniques into the phase-sensitive method

Acral-type Malignant Acanthosis Nigricans Associated with Gastric Adenocarcinoma

Acanthosis nigricans is a symmetric eruption characterized by the presence of a hyperpigmented, velvety cutaneous thickening, that can develop on any part of the body, but characteristically affects the flexural areas of the body. The velvety hyperkeratotic lesions can be located on the dorsum of the hands and feet in dark-skinned people in the form of a variant of acanthosis nigricans called as acral acanthotic anomaly or acral type acanthosis nigricans. Although acanthosis nigricans is associated with malignant tumors, particularly gastric carcinoma, acral type acanthosis nigricans has never been reported to be associated with gastric adenocarcinoma. In our present study, we describe a case of 58-year-old man with acral type acanthosis nigricans and its association with carcinoma of the stomach; a marked improvement was seen in the skin condition of the patient with chemotherapy

Pseudocyst of the Scalp

Pseudocyst of the scalp is described in the Japanese literature as a skin-colored cystic tumor localized on the forehead, whereas alopecic and aseptic nodules of the scalp are described in the French literature as asymptomatic nodules on the scalp that lack a pseudocyst-like architecture. The etiology of these diseases is unknown, but the lesions are likely due to follicular occlusion. Here, we report a case of pseudocyst of the scalp in a 72-year-old woman. The patient had a dome-shaped painless tumor on her scalp. Histologic examination showed a pseudocyst-like architecture with no true cystic wall. Here, we report a case of pseudocyst of the scalp and summarize the characteristic features of both pseudocyst of the scalp and alopecic and aseptic nodules of the scalp

Treatment of Disseminated Classic Type of Kaposi's Sarcoma with Paclitaxel

Classic Kaposi sarcoma (KS) is a rare human herpes virus 8-associated angioproliferative disease, and the disseminated classic type of KS in Korea is even rarer. The treatment options for classic KS vary and range from surgical excision to ionizing irradiation or chemotherapy. Recently, there have been a few reports of treating classic KS with paclitaxel, which has been used to treat AIDS-associated KS and post-transplant KS. We herein report a case of disseminated classic type KS in a 78-year-old Korean male patient who showed dramatic response after only two cycles of paclitaxel treatment

The Appearance of a Candidate Site for a Primary Melanoma: A 5 Year-gap with a Melanoma of an Unknown Site

Although more than 90% of melanomas have cutaneous origins, melanomas sometimes present metastatically with no apparent primary lesion. A 62-year-old female presented with black pigmentation on her left thumbnail that had begun 2 years earlier and after the biopsy, she was diagnosed with malignant melanoma. Interestingly, 7 years earlier, a 4 cm palpable mass on her left axilla had been diagnosed as melanoma from an unknown primary site (MUP) with the involvement of an axillary lymph node. We speculate that the melanoma of the left thumb was the primary site and the melanoma in the axilla was a metastasis from the left thumb, and suggest several hypotheses explaining the appearance of the primary lesion as acral lentiginous melanoma after detecting a metastatic site. We consider this case interesting because it helps us to understand the pathogenesis of MUP and reminds physicians to conduct careful periodical work-ups of melanoma patients, and highlights the importance of continued long-term follow-up, especially for patients with MUP