Ct me supra renal mass liye kiya protocol hai or delays kitne der me lete hn
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CT adrenal suprarenal mass protocol phases timing delays radiology
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Yahan pe supra-renal (adrenal) mass ka complete CT protocol detail mein diya ja raha hai — textbooks aur SAR (Society of Abdominal Radiology) guidelines ke mutabiq:
CT Suprarenal (Adrenal) Mass Protocol
🎯 Indication ke mutabiq Protocol
Protocol 1 — Incidentaloma / Hyperfunctioning lesion (non-pheochromocytoma)
Phases aur Delays:
| Phase | Coverage | Delay | Slice Thickness |
|---|---|---|---|
| Pre-contrast (Unenhanced) | Adrenals only | — (baseline) | 1.5–3 mm |
| "Early" / Venous Phase | Adrenals only | 60–75 seconds post-contrast | 1.5–3 mm |
| Delayed Phase (Washout) | Adrenals only | 15 minutes post-contrast | 1.5–3 mm |
✅ Radiologist pehle pre-contrast images check kare. Agar ≤10 HU ho (lipid-rich adenoma) — toh contrast ki zaroorat nahi.
Protocol 2 — Suspected Pheochromocytoma
| Phase | Coverage | Delay |
|---|---|---|
| Early Phase only | Diaphragm se aortic bifurcation tak | 60–75 seconds |
⚠️ Washout phase typically nahi lete pheochromocytoma mein kyunki pheo bhi high washout show kar sakta hai — false negative ho sakta hai. MRI preferred hai.
📊 Washout Calculation (Adenoma vs Non-Adenoma)
Absolute Percent Washout (APW):
$$APW = \frac{(Enhanced HU - Delayed HU)}{(Enhanced HU - Unenhanced HU)} \times 100$$
- ≥ 60% APW → Adenoma (Sensitivity 98%, Specificity 92%)
Relative Percent Washout (RPW) (jab pre-contrast phase nahi ho):
$$RPW = \frac{(Enhanced HU - Delayed HU)}{Enhanced HU} \times 100$$
- ≥ 40% RPW → Adenoma
💉 Contrast Material
| Parameter | Detail |
|---|---|
| Type | Low-osmolar ya iso-osmolar |
| Volume | 100–125 mL (350 mg I/mL) |
| Injection Rate | 2–3 mL/second |
| kVp | Fixed 120 kVp (zaroor — kyunki literature 120 kVp par based hai) |
🔑 Key Points (Kya diagnose hota hai)
| Unenhanced HU | Diagnosis |
|---|---|
| < 10 HU | Lipid-rich adenoma — contrast ki zaroorat nahi |
| > 10 HU + APW ≥ 60% | Lipid-poor adenoma (atypical adenoma) |
| > 10 HU + APW < 60% | Non-adenoma (metastasis, ACC, pheo consider karo) |
Malignancy ke suspicious features:
- Size > 6 cm (>10 cm → 98% ACC risk)
- Irregular margins, heterogeneous enhancement
- Central necrosis / calcification
- IVC ya renal vein invasion
- Retroperitoneal lymphadenopathy
Summary — Delays at a Glance
| Phase | Delay |
|---|---|
| Pre-contrast | 0 (baseline) |
| Portal/Venous phase | 60–75 seconds |
| Washout (Delayed) | 15 minutes |
Sources:
- Campbell-Walsh-Wein Urology, Imaging Modalities section
- Hinman's Atlas of Urologic Surgery, Adrenal Imaging / CT section
- Society of Abdominal Radiology (SAR) CT Adrenal Mass Protocols v1.0
- AJR — Performance of CT with Adrenal-Washout Protocol (multi-institutional study)
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