Published on March 10, 2014
IMAGING MODALITIES OF DIAPHRAGM DR. ARIF KHAN S
DIAPHRAGM (S) • Diaphragm : Seperation • Thoracic Diaphragm • Pelvic Diaphragm • Urogenital Diaphragm
THORACIC DIAPHRAGM (ANATOMY) • Dome shaped • Muscular fibres : orgin Sternal – below XIPHOlD process , Costal - Inner surface of costal cartilages of 6th ribs , lumbar - Aponurotic arches of lumbar vertebrae
• lumbocostal arches : 2 pairs Medial lumbocostal arches : tendinous arch covering psoas major; continuous medially with left crura ; attached to L2 vertebral body and in the front of the transverse process of L1 and L2 Lateral lumbocostal arches : covers quadratus lumborum; attached medially to the L1 transverse process and attached laterally to the tip of the 12th rib • Crurae : Right and Left ; Blends to the Anterior longitudinal ligament of vertebrae • CENTRAL TENDON: Strong aponeurosis. below pericardium
Aortic Hiatus (T12) Oesophageal Hiatus (T10 ) Vena caval foramen (T8) Lesser apertures BLOOD SUPPLY At 1.Costal margins – lower 5 intercostal A. 2. Abdominal surface – Rt & Lt Inf.Phrenic A. 3. Superior phrenic A. And Musculophrenic A NERVE SUPPLY Rt and Left phrenic N. & inter –costal N.
NORMAL CHEST X-RAY
• Normal Diaphragm is 2-3 mm thick • Which is normally not measurable In right side unless there is free peritoneal gas or bowel loop separating the liver from diaphragm. • In the left side the combined stomach wall and diaphragm form linear density of 5-8 mm thick. • Thickening in most cases are normal. • Pathological thickening is seen in 1. Tumors of diaphragm; stomach & pleura 2. Subpulmonary fluid 3. Diaphragmatic humps 4. Abdominal lesions : splenomegaly, Hepatomegaly Sub-phrenic abscess
NORMAL VARIATIONS • Scalloping: Rt side common; • Muscle slips • Dipahragmatic humps and Dromedary hump • Eventration • Accessory Diaphragm
DIAPHRAGM (PHYSIOLOGY) • Function : Seperation between Thoracic and Abdominal cavities. Aid in Respiration as Chief Inspiratory muscle • Two components : non contractile central tendon ;contracting muscle fibres • Contraction of muscles induce intra-pleural pressure cause air to be sucked in the lungs • Contributes 3/4th of inspiratory volumes at the vital capacity. • Normal movement is 3-5 cm • Abnormal movement or reduced movement is seen in paralysis of diaphragm • Movement of diaphragm can be assessed using USG or Flouroscopy
PATHOLOGIES OF DIAPHRAGM
DIAPHRAGMATIC PARALYSIS • Due to injury to Phrenic nerve. • Unilateral or Bilateral • Increase load can cause respiratory failure • Assosciated with conditions like : Spinal cord transection, Multiple sclerosis, Amyotrophic lateral Sclerosis, Cervical spondylosis GBS, • Isolated Phrenic Nerve dysfunction: Compression by tumor, Cardiac surgery cold injury, blunt trauma, etc.
• Chest radiograph show elevated hemidiaphragm and Atelectasis of lung • Flouroscopy aid s in clear visualization of the movement of the diaphragm • Sniff Test: Parodoxical Elevation of diaphragm in inspiration • Other tests : PFT, EMG and phrenic nerve stimulation • USG
DIAPHRAGMATIC MOVEMENT ASSESSEMENT THORACIC ULTRASOUND: • Principles: • Changes in diaphragm thickness during contraction. (chronically paralyzed diaphragm is atrophic and does not thicken during inspiration ) • Should be assessed in two areas Liver at the Right and Spleen window on the left • Low frequency probes are used.
POST PROCEDURE INDUCED DIAPHRAGMATIC PARALYSIS (TRANSIENT TYPE)
FIG 1 FIG 2
RUPTURE OF DIAPHRAGM • Traumatic diaphragmatic injuries occur in 0.8%–8% of patients who sustain blunt trauma. Up to 90% of diaphragmatic ruptures from blunt trauma occur in young men after motor vehicle accidents • Both bilateral tears and extension of tears into the central tendon are uncommon. They are reported in 2%–6% of patients with diaphragmatic injury. • Mechanisms of injuries include a lateral impact, and shears the diaphragm, and a direct frontal impact
• Most ruptures are longer than 10 cm and occur at the posterolateral aspect of the hemidiaphragm between the lumbar and intercostal attachments and spread in a radial direction • Penetrating injuries such as gunshot wounds or stab injuries are more random Sites of injuries. Drawing shows radial (A), transverse (B), and central (C) ruptures and a peripheral detachment (D). Radial tears appear to be the most frequently found injury at surgery, whereas peripheral detachments are the least frequent.
ASSOSCIATED INJURIES • Common : pelvic fractures (40%–55%), splenic injuries (60%), and renal injuries • High frequency of liver injuries, which are more frequently associated with right than with left diaphragmatic tears • Thoracic injuries : pneumohemothoraces and rib fractures are seen in 90% of patients. Aortic thoracic injuries are reported in 5% of patients
DIAPHRAGM INJURY (IMAGING) Chest X-ray : (a) intrathoracic herniation of a hollow viscus (stomach, colon, small bowel) with or without focal constriction of the viscus at the site of the tear (collar sign) (b) visualization of a nasogastric tube above the hemidiaphragm on the left side • Findings suggestive of hemidiaphragmatic rupture include elevation of the hemidiaphragm, distortion or obliteration of the outline of the hemidiaphragm, and contralateral shift of the mediastinum
• CT CHEST: • Helical CT has proved to be more valuable in the detection of diaphragmatic injuries with a sensitivity of 71% • Findings : • 1. Direct discontinuity of the hemidiaphragm; sensitivity 73%, specificity 90%. • 2. Intrathoracic herniation of abdominal contents; sensitivity 55%, specificity 100%. • 3. The collar sign: sensitivity 36% with conventional CT 63% with helical CT. On the right side, the collar sign can appear as a focal indentation of the liver, a subtle sign easily overlooked • 4. The dependent viscera sign: sensitivity: 100%: left- sided 83%: right-sided when a patient with a ruptured diaphragm lies supine at CT examination, the herniated viscera (bowel or solid organs) are no longer supported posteriorly by the injured diaphragm and fall to a dependent position against the posterior ribs
CONGENITAL DIAPHRAGMATIC HERNIA • Diaphragmatic hernias include Bochdalek (posterolateral), Morgagni (retrosternal), and hiatal hernias • Antenatal USG scan can diagnose all types earlier • USG can in aid in determining the survivability of the foetus. • Congenital diaphragmatic hernia (CDH) is a major surgical emergency in newborns. The key to survival lies in prompt diagnosis and treatment • Pulmonary hypertension and Pulmonary hypoplasia are complications
MORGAGNI’S HERNIA • Anterior defect of the diaphragm • Retrosternal, or parasternal hernia • herniation through the foramina of Morgagni • Associated pericardial defect , pleural and or pericardial effusion may b seen • Contents : the liver, spleen, and omentum • D/d s Thymoma, Rt middle lobe collapse, hydatid cyst, fibrous tumor of the pleura Cardiophrenic angle lesions: lymphadenopathy : metastasis, lymphoma, reactional Pericardial Cyst ; pericardial lipomatosis
MORGAGNI HERNIA • Morgagni hernia in a 2-year-old child. Lateral chest radiograph shows herniation of a bowel loop (arrows) in a classic location through an anteromedial defect. • Anterior herniation of bowel loops on a lateral chest radiograph is the typical finding. Other herniated viscera include the liver, spleen, and omentum.
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BOCHDALEK HERNIA • Posterior aspect • defect in the posterior attachment of the diaphragm when there is a failure of pleuroperitoneal membrane closure in utero • most frequently left sided.
BOCHDALEK HERNIA • Frontal radiograph of the chest in a newborn shows herniation of bowel loops into the left hemithorax with displacement of the heart to the right, findings consistent with left Bochdalek hernia. • The nasogastric tube (arrows) in the left hemithorax indicates the intrathoracic stomach.
HIATUS HERNIA • A .K.a. oesophageal hiatal hernia • herniation of stomach through the oesophageal hiatus of the diaphragm • Types 1. Sliding 2. roling (para-oesophageal) Content : always Stomach ; rarely with bowel loops (if the defect is large enough) D/ds Lung abscess (Retro- cardiac) Empyema , epiphrenic oesophageal diverticulum
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CONGENITAL DIAPHRAGMATIC EVENTRATION • Abnormal elevation of part or all of an otherwise intact hemidiaphragm into the chest cavity is termed eventration. • CAUSES congenital absence of muscle fibers focal dyskinesia and weakness from ischemia, infarct, neuromuscular dysfunction. • The anteromedial aspect of the right side • D/Ds Morgagni hernia, pericardial cyst, paraesophageal hernia, bronchogenic cyst, and tumor.
• Focal eventration (arrow) at the anteromedial aspect of the right hemidiaphragm. • The eventration contains part of the liver.
• Eventration (arrow) at the left hemidiaphragm at seen at birth. • Complete eventration of a hemidiaphragm is more common in males and typically occurs on the left side.
TUMORS • Diaphragmatic tumors may be divided • : (i) primary benign neoplasms; • (2) primary malignant neoplasms; • (3) secondary malignant neoplasms; • (4) cysts; • (5) inflammatory lesions • (6) endometriosis.
PRIMARY BENIGN NEOPLASMS; • Can arise from any of the normal tissue components . Eg: Lipomas, fibromas, angiofi bromas, neurofibromas and neurilemmomas are common; Adrenal cortical adenoma, liver cell adenoma, chondroma, hamartorna and mesothelioma are rarer • Diagnosed mostly post mortem biopsy, • X-ray appearance as irregularity in diaphragm
PRIMARY MALIGNANT NEOPLASMS Majority are fibrous tissue origin. Eg; (fibrosarcoma, fibro-myo-sarcoma, fibro- angio-endothelioma) or undifferentiated sarcomas. • mixed cell sarcoma, myosarcoma, rhabdomyosarcoma, • Of the reported primary tumors of the diaphragm, malignant neoplasms predominate in a ratio of about 60 :40.
• SECONADARY MALIGNANT NEOPLASMS • Secondary malignant neoplasms of the diaphragm may he due to direct invasion • from adjacent lesions or metastatic spread OR through vascular channels. • Resembles benign tumours radiogrpahically. • Blood born mets are rare • Direct spread from lver ,lungs (incl pleura), stomach, kidneys adrenaals are seen ; • Others include chondro sarcoma , Hodgkin’s disease
SECONDARY DUE TO PRIMARY OVARIAN CARCINOMA
SPLENIC FLEXURE COLON CARCINOMA INVADING THRU DIAPHRAGM
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