HASTE MRU in the evaluation of acute flank pain.

A 20 year old, otherwise healthy, G2PO, 21 week pregnant female presented to the emergency department with a one day history of left flank pain, nausea, and vomiting. She denied a history of fevers, chills, or dysuria. Physical examination revealed left costovertebral angle tenderness. Laboratory evaluation was significant for leukocytosis (14,000), normal creatinine (0.6), and unremarkable urinalysis. Renal ultrasound demonstrated mild left hydroureteronephrosis without evidence of stone. Subsequent HASTE magnetic resonance urography (MRU) revealed a 3mm left ureteral stone, mild hydronephrosis, and a forniceal rupture (Figure-1). The patient was managed conservatively with hydration and oral narcotics. Urolithiasis is not an uncommon finding in pregnancy with an estimated incidence of 1/1,500 pregnancies (1). Although pregnancy does not confer an increased risk of urolithiasis, a shift in stone profile in pregnant patients has been observed. Specifically, there is an increased incidence of calcium phosphate stones as opposed to calcium oxalate stones most commonly observed in non-pregnant females. Reasons for this shift in stone composition include an absorptive hyercalciuria and relatively alkaline urine pH that occur in this population (2). Despite the common occurrence of stone disease in pregnancy, safe and accurate diagnosis remains a dilemma. When subjecting pregnant patients to diagnostic imaging studies the potential impact to the fetus must be considered. Computed tomography (CT), the gold standard for stone diagnosis, exposes the pa-