Select the single most appropriate diagnostic imaging modality for each patient scenario, taking into account their unique physiologic states, prior test results, and specific contraindications.
- An adult male with progressive paraparesis, fever, and urinary retention who possesses a legacy, non-conditional cardiac pacemaker.CT myelography of the spine
- A second-trimester gravid female presenting with sudden pleuritic chest pain and hypoxia, who carries a documented history of anaphylaxis to iodinated contrast media.Radionuclide ventilation-perfusion scanning
- A gravid female at 18 weeks gestation evaluated for focal right lower quadrant tenderness and leukocytosis, whose preliminary transabdominal sonography is indeterminate.Noncontrast MRI of the abdomen and pelvis
- An elderly individual unable to ambulate due to severe groin pain following a ground-level fall, whose initial conventional pelvic radiographs demonstrate no acute abnormalities.MRI of the affected hip joint
Cevap
The correct matches align each specific patient contraindication or equivocal preliminary result with its gold-standard alternative or definitive imaging modality.
The correct matches require applying evidence-based alternative imaging modalities when standard first-line tests are contraindicated or non-diagnostic. A legacy pacemaker precludes MRI, requiring CT myelography for spinal canal imaging. Severe iodine allergy precludes CT pulmonary angiography, making a V/Q scan the study of choice for suspected pulmonary embolism. Pregnancy necessitates avoiding ionizing radiation, making noncontrast MRI the test of choice for appendicitis after an indeterminate ultrasound. Finally, an occult hip fracture requires MRI for definitive diagnosis when plain films are unremarkable.
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Anahtar Kavram
Tailoring imaging modality selection based on specific patient contraindications, physiologic states, and the limitations of initial preliminary testing.
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