3/20/2017 Disclosures None Spectral CT in Body Imaging Initial - - PDF document

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Spectral CT in Body Imaging Initial experience

Gopal Punjabi Hennepin County Medical Center

Disclosures

▪None

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Conventional CT

Image equivalent to any CT image Generated by combining high and low energy components Mono-energy image equivalent to 120kVp tube output (70keV) Less artifact Increased contrast

MonoE 70 keV (equivalent to conventional CT)

Image with iodine removed

Virtual non-contrast

Attenuation as if a single monochromatic energy were used to scan 161 energy levels between 40-200 keV Iodine boost, CNR Artifact reduction

Mono energy

200 keV monoE 40 keV monoE 200 keV monoE

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Material density image Shows iodine concentration (Also shows calcium)

Iodine no water

Material differentiation Iodine concentration mg/ml Removes calcium

Iodine density

Tissue differentiation Iodine uptake

Effective Z

Isolates pixels where iodine is present Used best as overlay

Contrast enhancing structures Iodine removed

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200 keV monoE Effective Z

Uses of spectral CT

▪ Incidentaloma characterization ▪ Iodine detection ▪ Contrast dose reduction ▪ Perfusion marker ▪ Quantification ▪ Lesion characterization

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Simple cyst, no iodine uptake Conventional Virtual non-con Iodine no water Conventional Virtual non-con Iodine no water Hemorrhagic cyst, no iodine uptake Indeterminate kidney lesion 37 HU Conventional Iodine no water Conventional HU: 24 Virtual non-con: 1.6 HU “pseudoenhacement” in benign kidney cyst Iodine no water Conventional: 76 HU Virtual non-con: 29 HU Iodine no water Renal cell carcinoma

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Left: 42 vs 6 HU Right: 56 vs 11 HU Conventional Virtual non-con Bilateral adrenal adenomas Conventional: 57 HU Virtual non-con: 5 HU Indeterminate left adnexal lesion (24 HU) Conventional Virtual non-con Iodine no water Hemorrhagic cyst Indeterminate nodule in urinary bladder Conventional Iodine no water 40 keV monoE

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Conventional: 47 HU Virtual non-con: 24 HU

Iodine detection

Conventional 40 Kev monoE

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Conventional Iodine no water 40 Kev monoE

MPA Muscle Conventional 115 52 40 keV MonoE 287 35

Conventional 40 keV monoE Pseudoaneurysm Conventional 40 keV monoE Conventional 40 keV monoE Conventional 40 keV monoE

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40 keV monoE DWI, b 800 Conventional, iodine density Pyelonephritis Conventional 40 keV monoE Conventional 40 keV monoE

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Iodine no water Iodine no water Conventional Acute DVT Conventional Virtual non-contrast

Contrast dose reduction

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CT aorta 25ml contrast 250 HU CT aorta prior exam 100 ml contrast 300 HU Conventional 40 keV monoE

HCMC protocol (GFR <45)

▪ Injection volume: (Scan delay + Scan time) x 4 in mL ▪ Injection composition (contrast/saline mix): ▪ Injection rate: 4 mL/sec ▪ 30 mL saline chaser

Body weight Contrast % <150 pounds 40% 150-250 pounds 50% >250 pounds 60%

37 mL Omnipaque 350

Conventional 40 keV monoE

63 yo F GFR 38, BMI 51 28 mL Omnipaque 350 19 mL Omnipaque 350

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45 keV monoE

37 mL Omnipaque 350

40 keV monoE Conventional

22 mL Omnipaque 350

Perfusion marker

Conventional Iodine density Iodine density 40 keV Mono-E

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Conventional Iodine density 2 months prior… Conventional 40 keV monoE Iodine no water Conventional Iodine no water Iodine no water We immediately saw a loop of ischemic small bowel, about 30 cm, that was bound by a very small thin adhesion. This adhesions was lysed with cautery and the bowel was untwisted. The bowel loop was clearly not viable.

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Findings concerning for bowel

• bstruction from sigmoid
• volvulus. While there is new

ascites, there is no frank pneumatosis or free air at this

• time. Recommend surgical

consult. Conventional Iodine no water Iodine density Conventional

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Iodine no water Conventional Conventional Iodine no water Conventional 40 keV monoE

Quantification

Provoked PE, hemodynamically stable, no RV strain Lovenox to Xarelto Patient with HIV, CAD with chronic angina, anxiety and depression

Unclear why the pt acutely decompensated

• vernight. He had high ventilation demands,

however, was had a minute ventilation around 24. The differential includes V/Q mismatch from mucous plugging vs pleural effusion.

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Normal Ischemic 2.1 +/- 1.03 0.3 +/- 0.18 2.4 +/- 0.8 0.4 +/- 0.35 Normal Ischemic 2.4 +/- 0.4 1.4 +/- 0.38 2.1 +/- 0.53 1.1 +/- 0.38 Conventional Iodine no water

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Tissue Iodine uptake Normal pancreas 3.3 +/- 0.04 Spleen 4.1 +/- 0.05 Liver 1.7 +/- 0.05 Muscle 0.4 +/- 0.09 Necrosis 0.9 +/- 0.05 Conventional Iodine density Iodine density Appendix 1.4 +/- 0.1 Cecum 0.8 +/- 0.1 HU Iodine density Appendix 88 +/- 14 2.1 +/- 0.12 Cecum 71 +/- 8 1.5 +/- 0.05 Conventional Iodine density Conventional

Lesion characterization

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Conventional Iodine no water Virtual non-contrast Conventional Iodine no water Virtual non-contrast Conventional 40 keV monoE HU Iodine density Liver cyst 50 +/-12 0.2 +/- 0.06 Liver met 54 +/- 9 0.8 +/- 0.09 Pancreas ca 43 +/- 13 0.8 +/- 0.29 Late arterial phase Delayed phase

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Conventional Virtual non-contrast 200 keV monoE

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Conventional Iodine no water Endometrial thickening, mass versus hemorrhage Conventional Iodine no water Radiology: Volume 276: Number 3 September 2015

Thank you!