CT

CTDIvol is best described as what kind of quantity?

Dose–length product (DLP) is defined as:

Reducing mAs by 50% (all else equal) changes CTDIvol how?

Increasing pitch (other factors constant) generally does what to patient dose?

Lowering kVp for iodinated CTA typically:

Angular tube current modulation (x–y) primarily:

Longitudinal (z-axis) modulation primarily:

Effective mAs on some scanners refers to:

Thicker reconstructed slices affect image noise how?

Using a sharper (bone) kernel generally:

Pixel size in the image matrix is determined by:

Pitch in MDCT is defined as:

Partial volume averaging is reduced by:

Beam-hardening artifacts are reduced by:

The primary purpose of the bowtie filter is to:

Metal artifact reduction can be achieved by:

Motion artifacts are minimized by:

In pulmonary CTA for PE, optimal bolus timing uses:

Test-bolus method involves:

Prospective ECG-gated coronary CTA compared with retrospective gating typically:

Typical contraindication or caution for iodinated IV contrast is:

Immediate management of contrast extravasation includes:

For a mild allergic-like reaction (limited urticaria) during CT contrast injection, the first-line action is:

Reducing kVp from 120 to 100 (adjusting mAs to maintain noise) usually:

SSDE (size-specific dose estimate) requires:

Over-ranging (z-overscanning) in helical CT:

Increasing matrix from 512 to 1024 (same FOV) mainly:

Iterative reconstruction (IR) compared with FBP typically:

Dual-energy CT can reliably help differentiate:

For CT urography multiphasic protocols, the excretory phase is timed to:

In chest CT for ILD, recommended acquisition includes:

Increasing slice thickness from 1.25 mm to 5 mm will generally:

Best way to reduce breathing artifacts in abdomen/pelvis CT:

For CT brain without contrast in suspected acute hemorrhage, the key technical priority is:

Window width/level adjustments:

Typical HU values are approximately:

For obese patients in abdomen CT, dose-efficient strategies include:

Coronary CTA image quality is best when heart rate is:

In CT colonography, a critical preparation step is:

Pediatric CT dose optimization emphasizes:

Prominent streaks through the shoulders on low-dose chest CT are most consistent with which artifact, and what adjustment best reduces it?

A circular “ring” on every image slice most commonly indicates:

Central regions of a uniform phantom appear darker than edges (“cupping”). What is the cause?

Spiral “windmill” streaks in wide-detector helical scans are reduced by:

“Stair-step” edges on MPRs of thick reconstructions are best prevented by:

Anatomy clipped at the edges with bright/dark streaks is typical of:

Calcified coronary plaque appears larger than reality on CTA due to:

In dual-energy CT, which reconstruction best reduces metal streaking?

Cardiac CT temporal resolution depends primarily on:

Why use a saline chaser after contrast injection in CTA?

For abdominal arterial phase CTA, the bolus tracking ROI is ideally placed in the:

Hypervascular liver lesions (e.g., HCC) are most conspicuous in which phase?

Pancreatic adenocarcinoma conspicuity is optimized during which phase?

The nephrographic phase of CT urography is primarily used to:

Best initial CT protocol for suspected renal stone:

Lung cancer screening uses which CT technique?

Maximum intensity projection (MIP) primarily helps with:

Minimum intensity projection (MinIP) is most useful for:

Preferred kernel choices: lung detail vs soft tissue?

Water CT number in QC should be approximately:

Slice sensitivity profile (SSP) width primarily improves when you:

Over-beaming refers to:

CT number linearity QA uses:

Performing a fresh air calibration before scanning primarily helps prevent:

Dual-energy iodine maps are useful because they:

For contrast extravasation > small volume with pain/swelling, initial management is:

Delayed allergic-like reactions to iodinated contrast typically occur:

Regarding metformin and iodinated contrast, the safest general statement is:

CT colonography technique benefits from scanning:

Accurate lung nodule measurement requires:

Tube current modulation (ATCM) is best described as:

Increasing the target noise index (acceptable noise) on ATCM generally:

Gantry tilt in head CT is used primarily to:

Lowering kVp in iodinated studies usually:

Coronary CTA vessel visualization is improved pharmacologically by:

Coronary calcium scoring (Agatston) requires:

In the head, streaks from the skull base due to very dense bone are reduced by:

The most effective single step to reduce breathing motion in abdomen CT is:

Effective dose from CT is estimated by multiplying:

To reduce extravasation risk during power injection, prefer:

Which change most reliably lowers CT dose while preserving target image noise?

Compared with filtered back projection (FBP), model-based iterative reconstruction typically:

For iodinated CTA in small/medium patients, lowering kVp from 120 to 100 usually:

Prospective ECG-gated coronary CTA versus retrospective helical gating generally:

Which combination best limits over-ranging in helical CT?

CTDIvol primarily scales with which parameter (others fixed)?

Size-specific dose estimate (SSDE) differs from CTDIvol because it:

Photon starvation streaks in shoulders on low-dose chest CT are best mitigated by:

A uniform “ring” artifact on every slice most often indicates:

The bowtie filter primarily:

For pulmonary CTA (PE study), optimal bolus timing uses:

Best initial CT for suspected renal stones is:

In liver imaging, HCC is typically most conspicuous during:

Pancreatic adenocarcinoma visibility is optimized during:

In CT urography, the excretory phase is primarily for:

Typical unenhanced CT criterion favoring lipid-rich adrenal adenoma is:

Which step best reduces metal streak artifacts?

To reduce breathing motion on abdomen CT, prioritize:

In acute stroke imaging, the first-line CT exam is:

In CT brain perfusion, an ischemic core classically shows:

Dual-energy CT can confidently differentiate:

For lung cancer screening, protocol is:

Accurate nodule follow-up measurement requires:

Water CT number during QC should be approximately:

Increasing matrix from 512 to 1024 at the same display FOV primarily:

Partial-volume averaging is minimized by:

“Windmill” artifacts on wide-detector helical scans are reduced by:

Truncation artifact occurs when:

Why use a saline chaser in CTA?

For coronary CTA, image quality is improved by:

In obese patients, dose-efficient abdomen CT uses:

For CT colonography, technique is optimized by:

Which parameter chiefly determines temporal resolution of cardiac CT?

A measured DLP of 300 mGy·cm for a chest CT corresponds to effective dose estimation by:

After mild immediate urticaria from contrast, first-line management is:

Regarding metformin and contrast, a prudent statement is:

The best single preventive step for contrast-associated acute kidney injury is:

Gantry tilt in head CT is particularly useful to:

Which change most improves depiction of small lung nodules on MPRs?

The most important pediatric CT principle is to: