Optimization of a protocol for contrast-enhanced four-dimensional computed tomography imaging of thoracic tumors using minimal contrast agent

Purpose The accuracy of target delineation for node-positive thoracic tumors is dependent on both four-dimensional computed tomography (4D-CT) and contrast-enhanced three-dimensional (3D)-CT images; these scans enable the motion visualization of tumors and delineate the nodal areas. Combining the two techniques would be more effective; however, currently, there is no standard protocol for the contrast media injection parameters for contrast-enhanced 4D-CT (CE-4D-CT) scans because of its long scan durations and complexity. Thus, we aimed to perform quantitative and qualitative assessments of the image quality of single contrast-enhanced 4D-CT scans to simplify this process and improve the accuracy of target delineation in order to replace the standard clinical modality involved in administering radiotherapy for thoracic tumors. Methods Ninety consecutive patients with thoracic tumors were randomly and parallelly assigned to one of nine subgroups subjected to CE-4D-CT scans with the administration of contrast agent volume equal to the patient’s weight but different flow rate and scan delay time (protocol A1: flow rate of 2.0 ml/s, delay time of 15 s; A2: 2.0 ml/s, 20 s; A3: 2.0 ml/s, 25 s; B1: 2.5 ml/s, 15 s; B2: 2.5 ml/s, 20 s; B3: 2.5 ml/s, 25 s; C1: 3.0 ml/s, 15 s; C2: 3.0 ml/s, 20 s; C3: 3.0 ml/s, 25 s). The Hounsfield unit (HU) values of the thoracic aorta, pulmonary artery stem, pulmonary veins, carotid artery, and jugular vein were acquired for each protocol. Both quantitative and qualitative image analysis and delineation acceptability were assessed. Results The results revealed significant differences among the nine protocols. Enhancement of the vascular structures in mediastinal and perihilar regions was more effective with protocol A1 or A2; however, when interested in the region of superior mediastinum and supraclavicular fossa, protocol C2 or C3 is recommended. Conclusion Qualitatively acceptable enhancement on contrast-enhanced 4D-CT images of thoracic tumors can be obtained by varying the flow rate and delay time when minimal contrast agent is used.

Percutaneous Transhepatic and Translumbar Sclerotherapy of a Thoracic Duct Cyst: A Case Report

A 58-year-old male presented with chronic abdominal pain lasting 5 years and a 15 × 6-cm multicystic thoracic duct cyst with three compartments, located in the right retrocrural and retrocardiac regions from T5/T6 to T12/L1. A transhepatic route was selected to sclerose the middle and lower compartments. Subsequent contrast injection showed minimal contrast passage into the upper compartment through a narrow neck, but the guidewire could not pass into this compartment. The contrast-filled upper compartment was punctured with a 22-g Chiba needle using a translumbar approach under cone-beam computed tomography (CT) guidance and ethanol sclerotherapy was performed. Six-month follow-up CT revealed decreased thoracic duct cyst size (5×3 cm) and no pain. This case illustrates successful percutaneous transhepatic and translumbar sclerotherapy for retrocardiac and retrocrural thoracic duct cysts, which are very difficult to remove surgically.

A young woman with multiple acyl-CoA dehydrogenase deficiency (MADD)

A 31-year-old female hairdresser whose parents were first degree cousins complained of episodic attacks of headache, vomiting, and dizziness for the past eight years after an uneventful childhood and adolescence. Four years ago, she developed progressive weakness, muscle pain and difficulties walking and lifting her arms that she could not work in her profession anymore. She lost hair, weight and became amenorrhoic. Finally, her muscle weakness required intensive care. Early on her CK was mildly elevated to 237 U/l (normal < 167), but later to 900 and 1800. By MRI, skeletal muscles showed minimal contrast enhancement.The clinically suspected diagnosis of myositis prompted repeated muscle biopsies, which disclosed non-specific myopathic changes, scattered necrotic muscle fibers without inflammation, protein aggregation, or vacuolation by light microscopy, but abnormally structured mitochondria with inclusions by electron microscopy, and treatment with steroids without any clinical improvement.A panel of 1131 mitochondrial genes revealed a homozygous mutation in the ETFDH gene.LEARNING OBJECTIVESThis presentation will enable the learner to: 1.Discuss MADD as a mitochondrial and lipid storage disease2.Recognize the myopathology of MADD

Acquisition of phonology in child Icelandic Sign Language: Unique findings

Research shows that acquisition of sign language phonology is a developmental process and involves multiple articulatory cues. Among these cues, handshape has been shown to be crucial and orientation has been argued to be potentially disregardable as being internal to sign production rather than encoding a minimal contrast. We administered a non-word repetition task and a picture naming task to 17 (age 3-15) deaf and hard-of-hearing signers of Icelandic Sign Language (ÍTM)—an endangered indigenous language of the Deaf community in Iceland—targeting the same articulatory features. The tasks were modeled after similar assessment tools for other languages. All of the participants use ÍTM for daily activities at school and at home; the vast majority were early learners (before 36ms). Results show an upward trajectory in the non-word repetition task scores but without a ceiling effect. Contrary to predictions, no effect of handshape was observed. Instead, on both pseudo- and real-word tasks, the majority of errors were in orientation/mirroring. The results suggest that orientation plays a non-trivial role in acquisition of sign language phonology