Although a CT scan is required for some Emergency Department patients with signs and symptoms of a kidney stone, recent evidence has shown that routine scanning is unnecessary and may expose young patients to significant cumulative radiation, increasing their risk of future cancers. Shared Decision-Making may facilitate diagnostic imaging decisions that are more inline with patients' values and preferences. By comparing a shared approach to diagnostic decision-making to a traditional, physician-directed approach, this study lays the foundation for a future randomized trial that will reduce radiation exposure, improve engagement, and improve the quality and patient-centeredness of Emergency Department care.

Inclusion Criteria:

1. Age 18-55,
2. with acute flank pain - for whom clinician believes acute flank pain may be from renal colic
3. who are deemed by the treating clinician to be at low risk for dangerous alternative diagnoses.
4. Clinician is considering imaging patient for kidney stones (any imaging)

Exclusion Criteria:

1. Recent trauma related to pain (including minor such as lifting/turning)
2. Pregnancy (previous or discovered during ED visit)
3. Recent surgical procedure on abdomen or pelvis (30d)
4. Recent urologic procedure (30d)
5. Recent childbirth (30d)
6. Signs of Systemic Infection: Fever >100.9 (101 and up), SBP <90, HR>120
7. Moderate or severe abdominal tenderness or rebound/guarding, consistently present (present for more than one exam, or present after patient treated with pain medication)
8. Second doctor's visit (ED, PCP, urgent care) for THIS episode of pain (previous similar visits ok if pain gone for >30d in between episodes) (if seen at PCP or urgent care in same day or 24 hour period, this is not an exclusion, but if seen at PCP/urgent care or ED 1-30 days prior to index visit, with same pain, excluded)
9. Known history of one kidney or other urological/renal abnormality (including neurogenic bladder, ESRD and paraplegia; or if solitary kidney discovered on US)
10. Known malignancy (any) within past year (or received treatment in the past 12 months)
11. Immunocompromised (chronic steroids, HIV, crohns, immunomodulators or severely ill chronically)
12. On anticoagulation
13. Crisis patient (behavioral health)/belligerent
14. Lacks capacity for medical decision-making
15. Unlikely to respond to follow-up calls (IVDA, homeless, no phone)
16. Clinician is concerned for alternative diagnosis requiring CT scan (appendicitis) (>5% likelihood by clinician gestalt)
17. Patient is not improving clinically and clinician is considering admission

There is no current plan for data sharing. This could change.