Double aortic arch with an atretic left arch distal to the origin of left subclavian artery was diagnosed with multi-detector row computed tomography (MDCT) in two children with dysphagia. This rare type of complete vascular ring is clinically important because it may be confused with right aortic arch in mirror imaging. Anatomic details of this rare type of complete vascular ring demonstrated on MDCT facilitated appropriate surgical treatment.

The method of multiple injections coupled with graphite furnace and atomic absorption spectrometry is applied to direct determination of total chromium at extremely small concentrations in samples of open sea water. The method involves the in situ preconcentrarion of trace chromium in sea water onto a pyrocoated graphite tube by multiple injections (up to 4 x 90 ,uL) prior to analysis. The selected ashing temperature is up to 1800°C, and the background signal caused by high sea-salt contents will be markedly reduced when the ashing time is prolonged up to 200s. A CASS-2 reference sea water has been used as a quality control sample in the analyses of samples of open sea water samples; the results were found to agree with the certified value. Due to the use of a relatively large volume (up to 0.36 mL) of sample for direct determination of trace chromium in sea water, the detection limit for chromium is 0.057 ppb. 241

Multiple myeloma is a hematopoietic cancer that is multicentric and most commonly involves the spine. Multiple myeloma with extraosseous and intradural involvement is an extremely rare condition. Here we present a rare case of spinal multiple myeloma with intracranial and spinal intradural metastasis causing lumbar spinal nerve compression. We present a 60-year-old woman with progressive weakness of the lower limbs for several weeks. Spinal magnetic resonance imaging (MRI) showed a leptomeningeal tumor with nodularity spreading within the cauda equina. Examination of the brain using MRI showed a lytic skull bone lesion and leptomeningeal enhancement. The patient underwent L3-5 laminectomy. Immunohistological staining confirmed a diagnosis of multiple myeloma of the IgA kappa subtype. After surgery, the patient underwent chemotherapy and rehabilitation exercises. Multiple myeloma has a median survival of 2.5 years, while 75% of patients with spinal involvement die within 1 year of diagnosis. Unfortunately, our patient died 3 months after the diagnosis of multiple myeloma with spinal and intracranial involvement. Intracranial and spinal intradural multiple myeloma invasions are quitely rare. Spine biopsies and cerebrospinal fluid cytology can aid in the diagnosis. Early surgical decompression is necessary, especially when neurological deficits occur.

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