M I T R A K H AL I L I M D

Rational Imaging Investigation For Common Diseases

BASIC CONCEPTS IN DIAGNOSTIC IMAGING

Modalities Available in Radiology

Plain Film / X-Ray/Mammography

Fluoroscopy

Ultrasound

CT

MRI

Nuclear Medicine/Molecular Imaging

Angiography/Interventional

X-Rays

Most widely performed imaging exam

X Rays are emitted and detected in cassette

Cassette can generate either a film or a digital image

Films are kept ‘on file’ or in a digital archive

Most Useful Applications for Plain X-Rays

Chest

Musculoskeletal

Abdomen: limited usefulness

Fluoroscopy

Utilizes X-Rays

Real-time imaging

Utilizes image intensifier

Involves use of contrast agents

Main Uses of Fluoroscopy

Gastrointestinal Imaging

Genitourinary Imaging

Angiography

Other

Intraoperative

Foreign body removal

Musculoskeletal

Gastrointestional Fluoroscopy

Barium Swallow

Upper GI

Small Bowel Series

Enteroclysis

Contrast Enema

Defecography

Single Contrast vs Double Contrast

Single Contrast Generally uses just thin Barium

Distends lumen with high density material

Easier for patient/less mucosal detail

Double Contrast/Air Contrast Thick barium coats lumen

Effervescent tablets ingested to distend lumen with air

Produces ‘see-through’ images with greater mucosal detail

Greater sensitivity for small lesions, polyps, ulcers

Genitourinary Fluoroscopy

Cystogram

Voiding cystourethrogram

Retrograde urethrogram

Hysterosalpingogram

Cystogram

Usually in adult patients

Looking for tear or intraluminal mass

Catheter placed and bladder filled with contrast to capacity: usually 300-500 ml.

Spot films obtained when full

Post void film: usually overhead

Voiding Cystourethrogram VCUG

Usually in children with history of UTI

Searching for vesicoureteral reflux

In males, evaluate for urethral abnormalities: posterior urethral valves

Same as cystogram except when full patient voids under fluoro with spot films

Retrograde Urethrogram RUG

Male patients

Pelvic Trauma

Post-infectious: STD- looking for stricture

Different techniques

Meatus occluded and contrast injected into urethra under fluoro

Hysterosalpingogram

Used to evaluate endometrial canal and fallopian tubes

Infertility and uterine anomalies

Dye injected into cervical os under fluoro

Injection continued with goal to opacify the fallopian tubes and spill contrast into peritoneum

Computed Tomography (CT

• Cross Sectional imaging modality

• Mobile X-ray tube that rotates around a patient Slices of X-ray transmission data reconstructed to generate image

• Data displayed in multiple window settings (lungs parenchyma, bone, etc.)

• Density measurements/Hounsfield Units analyze chemical component of tissue HU: -150-0 = fat, 0 = water, 0-20 = serous fluid, 45-75 = blood, 100-1000 = bone/calcium

CT Contrast Agents

• Intravenous contrast: Differentiate blood vessels vs. vascular internal organs

• Enteric contrast: Differentiate bowel vs. intra-abdomina fluid/masses

• Rectal contrast

• Retrograde urinary bladder contrast

CT Applications

• Neuro-imaging

-Acute head trauma, acute intracranial hemorrhage

-Low sensitivity for early ischemic stroke, intracranial metastatic disease, white matter degenerative disease

• Head and Neck imaging -Soft tissue of neck, paranasal sinuses, temporal

bone imaging, orbital wall imaging

CT Applications

• Body Imaging

-Chest, Abdomen, Pelvis (with enteric and IV contrast)

-Pulmonary nodules, Renal Calculi (without

contrast)

-Acute appendicitis (with enteric and IV contrast)

-Specialized protocols: Liver masses, pancreatic tissue, renal masses, adrenal masses

CT Applications

• Acute Abdomen

-decrease rate of false laparotomy procedures

• Trauma Spine Imaging (cervical, thoracic, lumbar)

• Other osseous structures (pelvis,

extremities)

• Vascular Imaging

-CT angiography--- i.e. coronary arteries

Magnetic Resonance Imaging (MRI)

• Multi-planar scanning without ionizing radiation

• Images generated using powerful magnets and pulsed radio waves passing through the body

• Data from Pt’s body used to generate image

• Field strength of magnets 0.3-3.0 Tesla

MR Applications

• Neuro-imaging

-Excellent tool due to high soft tissue contrast resolution

-Abundant water content of CNS allows for imaging soft intracranial tissue

• Head and Neck imaging -Multi-planar capability allows for monitoring

extent of disease

-Differentiating subtle soft tissue boundaries of head and neck

MR Applications

• Body Imaging

-Thorax: mediastinal, hilar, chest wall

abnormalities

-Limited lung imaging due to artifacts

• New advances in breast imaging

• Potentials for cardiac MRI with coronary MR angiography

MR Applications

• MSK Imaging

- High sensitivity for neoplastic, inflammatory, and traumatic conditions of bone and soft tissue

- T1-weighted---fluid collections and abnormalities in fatty marrow

- T2-weighted---lesions in both marrow and soft tissue

Respiratory system

Routine admission and preoperative CXR: - Admission chest radiographs were recommended only on patients with

clinical findings of cardiopulmonary disease or elderly patients unable to provide an accurate history or undergo a reliable physical examination.

- preoperative chest radiograph : advanced patient age (especially >70 years) and certain other patient- and procedure-related risk factors (eg, history of cardiopulmonary disease, unreliable history and physical examination, high-risk surgery) .

- Decision should derive to investigate a clinical suspicion for acute or unstable chronic cardiopulmonary disease that could influence patient care.

Portable CXR in ICU - Daily in acute cardiopulmonary problems - CXR after specific procedure - CXR for presence or course of disease

Respiratory system

Acute respiratory illness in immunocompetent patient:

- >40 y/o

- Dementia

- Hemoptysis

- Positive physical exam

- Associated abnormality ( WBC, hypoxemia)

- CHF, coronary artery disease, drug induced acute respiratory disease

Respiratory system

CXR in COPD:

- Complications such as pneumonia or pneumothorax, CHF, coronary artery disease ,chest pain, leukocytosis,edema

Respiratory system

CT in ARI:

- severe pneumonia

-Febrile neutropenic patient with normal CXR

- Clinical suspicious for SARS or H1N1 and normal CXR

Respiratory system

ARI in immunocompromised patient:

- CXR

- CT

Respiratory system

Dyspnea:

-CXR : Chronic, severe,>40 y/o,cardiovascular or pulmonary or neoplastic disease

- HRCT: When CXR is non revealing or it reveal abnormality but no definitive diagnosis

Respiratory system

Hemoptysis : Common causes include chronic bronchitis, bronchiectasis, pneumonia, fungal infections, tuberculosis, and malignancy and rarely vasculitis.

- CXR

- CT : suspicious chest radiograph findings or risk factors (>40 years of age, >30 pack-year smoking history).

- MDCT angiography : If hemoptysis recurs

Massive hemoptysis : Contrast-enhanced MDCT prior to embolization or surgery can define the source of hemoptysis as bronchial systemic, nonbronchial systemic, and/or pulmonary arterial.

Respiratory system

Screening for pulmonary metastasis:

- CXR: baseline

- CT: Bone and soft tissue sarcoma, melanoma and head and neck carcinoma, RCC and testicular carcinoma with elsewhere metastatic disease

Respiratory system

Rib fracture:

- CXR (PA view):indicated

- X-Ray rib view: usually not appropriate

- CT: usually not appropriate

GI system

Acute abdominal pain and fever Abdominal abscess in postoperative or nonoperative state:

- CT with contrast

Acute abdomial pain:

1. Perforation/Obstruction

- AXR and CXR

- CT: High clinical suspicious with negative X-Ray

- Ba study should not be used as a primary modality in diagnosis of small bowel obstruction.

GI system

2. Appendicitis :

-CT with oral and IV contrast : most accurate imaging

- US : in children

- MRI : in pregnancy with equivocal US exam

3. Pancreatitis :

- US : gallstone evaluation

- CT with iv contrast : choice

- MRI with iv contrast and MRCP

4. cholecystitis:

- US

GI system

Dysphagia:

- Barium swallow : Motility disorders and subtle stricture in comparison with endoscopy

Esophageal perforation :

- CXR

- Contrast swallow

- CT : sensitive for detection of perforation

Dyspepsia :

- Endoscopy : If negative or symptoms persist or alarm signs are present Barium meal

GI system

Jaundice :

1. Obstruction/ non obstruction

2. Benign/ malignant

3. Operative/ non operative

Stone : US / MRCP

Malignancy : Cross-sectional imaging ( CT / MRI )

GI system

Palpable abdominal mass :

- US and CT : First line procedure

GU system

Acute onset flank pain (stone?) : most complain

- CT without contrast : choice method

- IVP

- US and AXR : Children, pregnancy

Acute scrotal pain :

- Strong clinical suspicious to torsion : Explore

- Suspicious : Doppler ultrasound

- RNSI : Long examination time and less availability

GU system

Hematuria : - Gross hematuria clearly conveys a much higher risk of

malignancy than microscopic disease and should be thoroughly evaluated.

- Young women with a clinical picture of simple cystitis and whose hematuria completely and permanently resolves after successful therapy will probably not require any imaging as well as glomerulopathy.

- Risk factors such as cigarette smoking, occupational exposure to chemicals, irritative voiding symptoms, a full urologic evaluation for urothelial carcinoma is recommended if even one urinalysis documents microhematuria.

GU system

CTU : CTU is the first study in patients with hematuria .

Cystoscopy : The imaging evaluation will almost always be accompanied by cystoscopy to evaluate the urinary bladder

US : In patients who have contraindications to CTU or are sensitive to radiation (children and pregnant or child-bearing age women), or who have a very low risk of having a malignant cause of hematuria, US is the first-line imaging modality as well as patients with glomerular disease .

GU system

Most adults with gross or persistent microhematuria require urinary tract imaging, with CTU replacing the traditional IVU for this indication.

Although MRI is an excellent technique to evaluate the renal parenchyma for masses and other abnormalities, it is inferior to CTU and IVU in detection of small stones and urothelial lesions.

In the CT urogram, all patients receive water, primarily to hydrate the kidneys and distend the collecting system and ureter. Next, a noncontrast helical CT of the kidneys is obtained to evaluate renal calculi. This is followed by the injection of iodinated contrast media with the acquisition of a high-resolution (1- to 2-mm sections) nephrographic phase and a high-resolution delayed (five to 10 minutes) phase to evaluate for tumors and filling defects.

GU system

Acute pyelonephritis : - CT without and with contrast : No response to AB

therapy in 72h/ complicated adult (history of stone ,prvious urological surgery, repeated pyelonephritis) / DM or Immunocompromised without response

Pyonephrosis : - US exam VCUG : demonstrate vesicoureteral reflux and only

performed routinely in children. DMSA scan : pediatric population - US and DMSA scanning is recommended in children

after their first febrile UTI

GU system

Renal failure :

- US : First imaging modality : Separate chronic ESRD from reversible ARF with size/echo/hydronephrosis/cystic disease

- CT : Equivocal US for obstruction like stone or cystic disease

GU system

Renal trauma : 1. Blunt abdominal trauma and gross hematuria 2. Blunt abdominal trauma, shock (systolic pressure <90

mm Hg in the field or during resuscitation), or other associated injuries and microscopic hematuria

3. Blunt trauma with injuries known to be associated with renal injury such as rapid deceleration, direct contusion to the flank, flank ecchymoses, or fractures of the lower ribs or thoracolumbar spine, regardless of the presence or absence of hematuria

4. Penetrating trauma to the upper abdomen or lower thorax regardless of the presence or absence of hematuria.

GU system

Renal trauma :

- Hemodynamically stable patient (blunt and penetrating trauma): CT with contrast : modality of choice

- Only microscopic hematuria do not need radiological evaluation.

GU system

Bladder injury ( Penetrating or blunt ) :

- CT of the pelvis with bladder contrast (CT cystography) : first line

- X-ray retrograde cystography : filled view, and postdrainage radiograph

- X-ray RUG is the examination of choice for a suspected blunt perineal trauma in the male (straddle injury) and should be performed for suspected urethral injury from a penetrating trauma.

GU system

AUB :

- TVUS : Endometrial thickness is a well-established predicator of endometrial disease in post menopausal woman

Adnexal mass :

- US : Primary modality

- MRI : A problem solving tool

GU system

Acute pelvic pain in reproductive age:

- TVUS/TAUS : modality of choice in obstetric or gynecologic etiology

- CT : In gastrointestinal or genitourinary pathology

- MRI : In pregnant patients for nongynecologic etiologies

GU system

IUD :

- US

- AXR : only when IUD is not in uterine cavity

Breast imaging

Mammography is the only method of screening for breast cancer shown to decrease mortality.

Annual screening mammography is recommended starting at:

1) age 40 for general population; 2) age 25-30 for BRCA (BReast CAncer 1) carriers and untested relatives of BRCA carriers; 3) age 25-30 or 10 years earlier than the age of the affected relative at diagnosis (whichever is later) for women with a first-degree relative with premenopausal breast cancer or for women with a lifetime risk of breast cancer ≥20% on the basis of family history; 4) 8 years after radiation therapy but not before age 25 for women who received mantle radiation between the ages of 10-30; 5) any age for women with biopsy-proven lobular neoplasia, atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), or invasive breast cancer.

Breast imaging

US :

1. Identification and characterization of palpable and nonpalpable abnormalities and further evaluation of clinical and mammographic findings.

2. Guidance of interventional procedures.

3. Evaluation of problems associated with breast implants.

Breast sonography is the initial imaging technique to evaluate palpable masses in women under 30 and in lactating and pregnant women.

Breast imaging

MRI :

1. Screening

2. Extent of disease

3. Additional evaluation of clinical or imaging findings

MRI should not replace ultrasound or diagnostic mammography to evaluate clinical focal signs or symptoms in the breast or to evaluate lesions identified on screening mammography.

Breast imaging

For high-risk women, annual screening mammography and contrast-enhanced MRI are both indicated. US can be used for patients with contraindications to MRI.

For intermediate-risk women, annual screening

mammography is indicated. Contrast-enhanced MRI may be indicated in some patients.

For average-risk women, annual screening

mammography is indicated.

Breast imaging

Any highly suspicious breast mass detected by palpation or imaging should be biopsied.

Trauma

Blunt abdominal trauma_ Unstable patient :

1. CXR (portable)

2. US (FAST)

3. pelvic X-Ray

4. Lat. Cervical X-Ray

5. CT : Chest, abdomen and pelvic

Blunt abdominal trauma_ Stable :

- CT with IV contrast : First line

- CXR

- US (FAST)

Trauma

Blunt chest trauma : - CXR and chest CT/CTA are complementary first-line

imaging modalities in the workup of patients with high-mechanism blunt trauma.

- When initial trauma survey and mechanism of injury

suggest a low probability of significant thoracic trauma (normal mental status, normal clinical examination, and normal chest radiograph), further assessment with chest CT/CTA may not be necessary.

- suspected aortic injury CTA : First choice - TEE and MRA : alternative

Trauma

Head trauma :

- Minor or mild closed head injury (GCS≥ 13)without risk

factor or neurological deficit : No imaging

- Minor or mild closed head injury ,focal neurologic deficit, moderate or severe acute closed head injury in adults or children : CT without contrast

- Penetrating head injury , stable : CT without contrast

Trauma

Cervical spine trauma :

- Adult with low risk cervical spine trauma : No imaging

- Adult not low risk : CT ( Thin section with sagital and coronal reconstruction )

- Pediatrics : 3 view X-Ray

Trauma

Thoracolumbar spine trauma :

- CT : Choice

- MRI : Cord injury

- Imaging of entire spine when there is fracture of any segments

Trauma

MSK trauma :

- X-Ray : First imaging modality

- Reaeated radiograph/CT/MRI : High clinical suspicion

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