Recurring pain in your side or lower back that keeps returning deserves a kidney evaluation. Stones, swelling, and blood flow problems can all produce this pattern — and ultrasound checks all three.
Flank pain — that deep ache or sharp sensation in your side between the ribcage and hip — is one of the classic signs the kidneys may be involved. When it comes back repeatedly rather than resolving fully, it's usually pointing to something structural: stones that haven't passed, swelling from blocked drainage, or reduced blood flow to the kidney. These aren't conditions that wait. A renal ultrasound checks all three in a single study — without radiation, without a trip to the hospital.
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Recurring flank pain could be your kidneys. A renal ultrasound checks for stones, swelling, and blood flow issues — without radiation, at our Falmouth imaging center, this week. No referral. Results in 24—48 hours.
If your flank pain is accompanied by high fever, chills, severe nausea, visible blood in the urine, or pain so intense you cannot get comfortable — go to the emergency room or urgent care immediately. These may indicate an obstructing stone or kidney infection.
Recurring flank pain that keeps returning has a short list of common kidney-related explanations worth evaluating:
Kidney stones form when minerals crystallize inside the kidney. Small stones can pass on their own; larger ones obstruct the ureter and cause the intense, cramping flank pain most people describe as some of the worst pain they've ever experienced. Stones that pass partially and re-obstruct cause recurring pain. People who have had one stone have a significantly higher chance of forming another. A renal ultrasound can identify stones within the kidney and any resulting swelling — without the radiation exposure of CT imaging.
Hydronephrosis occurs when urine cannot drain properly from the kidney and backs up, causing the kidney to swell. Causes include obstructing kidney stones, scar tissue, or structural abnormalities. Even mild hydronephrosis can cause a persistent dull flank ache. Left untreated, the pressure buildup damages kidney tissue over time. A renal ultrasound evaluates kidney size and the degree of collecting system dilation — making it the first-line imaging study for suspected hydronephrosis.
Renal artery stenosis — narrowing of the arteries that supply blood to the kidneys — reduces kidney perfusion and can cause flank discomfort, hypertension that is difficult to control, and gradual kidney function decline. It's caused by atherosclerosis (plaque buildup) or fibromuscular dysplasia and is more common in people with high blood pressure, diabetes, or known vascular disease. A renal duplex ultrasound measures blood flow velocity in the renal arteries and can help identify abnormal flow patterns suggesting significant stenosis.
Not all flank pain comes from the kidneys. Muscle strain, rib issues, or spinal problems can produce a similar location and quality of discomfort. The key distinction is pattern: kidney-related pain often radiates toward the groin, is associated with urinary symptoms, and may come in waves (colic). Musculoskeletal pain tends to be more positional and reproduced by movement. If the renal ultrasound is normal, musculoskeletal causes become the more likely explanation.
A renal ultrasound is the right first-line study for recurring flank pain — comprehensive, radiation-free, and done at our Falmouth imaging center.
Renal Ultrasound · $397 in Falmouth
A comprehensive renal ultrasound evaluates both kidneys for size, cortical thickness, and structural abnormalities. Identifies stones within the renal collecting system. Detects hydronephrosis and grades its severity. With duplex technology, measures renal artery and intrarenal blood flow velocity to help identify stenosis. No radiation. No contrast agents. Performed at our Falmouth imaging center in approximately 45 minutes.
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Hydronephrosis that goes untreated damages kidney function over time — the longer the obstruction, the greater the functional loss. Renal artery stenosis is a correctable cause of resistant hypertension — but only once it's identified. Getting imaging promptly stops the guesswork and opens the door to intervention.
Our registered cardiac and vascular sonographer scans at our Falmouth imaging center, or comes to your home with portable ultrasound equipment. A single study is $397 in Falmouth or $597 at your home. No fasting required unless otherwise indicated. No waiting rooms, no hospital gown. You lie comfortably on your own bed or couch.
For the renal ultrasound, ultrasound gel is applied to your back and flanks. The transducer images both kidneys from multiple angles — evaluating size, cortical thickness, the collecting system for dilation, and any visible stones. With duplex Doppler technology, the probe also measures blood flow in the renal arteries entering each kidney and within the kidney itself (intrarenal resistive indices).
The entire scan takes approximately 30—45 minutes. It is completely painless and uses no radiation — making it safe to repeat if monitoring is needed over time.
Our sonographer walks you through key visual findings before leaving. The formal written report is delivered within 24—48 hours, ready to share with your primary care physician or any specialist involved in your care.
Recurring flank pain that doesn't fully resolve often points to kidney stones that pass partially and re-obstruct, hydronephrosis from blocked urine drainage, or renal artery stenosis reducing kidney blood flow. A renal ultrasound can help identify or rule out each of these causes in a single study.
Yes. Stones that are present within the kidney but not yet fully obstructing can cause intermittent discomfort. Stones can also recur in people who've had them before. A renal ultrasound can identify stones currently lodged in the kidney and any resulting hydronephrosis.
A renal ultrasound evaluates kidney size and shape, detects stones, assesses the collecting system for hydronephrosis, and with duplex technology measures renal artery blood flow velocity to help identify stenosis. Performed without radiation, making it safe for repeated use.
No referral is required. You can book directly through our website and book our Falmouth imaging center. Results are reviewed by a specialist and delivered within 24—48 hours.
Flank pain with high fever, chills, severe nausea, blood in the urine, or pain so severe you cannot get comfortable warrants urgent medical care. These may indicate an obstructing stone or kidney infection. Go to the emergency room or urgent care immediately. Mild to moderate recurring flank pain without these symptoms is appropriate to evaluate on a scheduled basis.
Southern Maine · Falmouth Imaging Center · No Referral
A renal ultrasound checks for stones, hydronephrosis, and renal artery blood flow — without radiation, at our Falmouth imaging center, this week. No referral. Flat pricing. Results in 24—48 hours.
Book Your Renal UltrasoundRenal Ultrasound $397 in Falmouth · No Referral · No Radiation · Southern Maine
